All right, as a tester I have different views on everything, I'm going to recollect on what I REMEMBER was changed and state opinions.
Megaman
He got slide with any weapon, (along with Proto and Bass) glitches fixed with the powerup items (some freeze glitches and such), gained LMS weapons (Bass and Proto do as well), and general got his game upped thanks to Jax's weapon system so ONLY copy classes can grab weapons.
Protoman
His shield was fixed since it didn't block specific things. For some time his charge shot's damage was reduced to 45 instead of 50, which I thought was great, but was reverted back due to whining of some sort.
Bass
Can't dash in air anymore, changes to how the double jump code works, and I think the speed of his bass buster shots was increased slightly.
Cutman
He lost his large jump, his alt is now slash claw like (I really liked this), his cutter is way faster (I don't like this but meh), and he can wall jump.
Gutsman
Only his punch was changed to a slash claw like attack. I find it silly but others find it useful. (Junkman has the exact same punch)
Iceman
Obviously his alt was changed, it did WAY more damage when it was first made and had infinite range! It killed Hardman in less than a second. To solve an argument here, Iceman is an "in your face" kinda class, so don't let him get near you.
Bombman
His alt was the main change here, problems here and there. Plainly its weaker than the thrown bomb but useful for chucking off cliffs.
Fireman
Woah boy changes everywhere on this guy. The rip from his main was removed and replaced with a mainfire shot that leaves a little flame that DOESN'T hurt any class with any sort of armor. He also has that shield like fire when firing his main and his alt fire's sounds were changed to be quieter. Finally, due to these changes and that it made him stronger, he became a "light" class robot master, meaning less armor.
Elecman
Elec changed from a "light" class fast guy, to a normal classy megaman guy. His mainfire shot was ever so slightly buffed in given a split shot like megamans. His alt was given a VISUAL appearance so you know if he used it. (PS. The lightning visuals do 1 damage haha.)
Oilman
His charge shot was buffed. Firing 1 oil with no charge, 3 oil with slight charge, and 5 oil with full charge. At first that 5 oil shot did 20 damage a hit, one hitting alot of classes, but that was weakened.
Timeman
There were glitches with Timeman's timeslow not affecting certain classes that was fixed. His overall damage was very slightly nerfed. Ex. Twin shot killed in 7 hits before (or 4 up close), now it kills in 10 hits (5 up close.)
Metalman
His jump height was increased, his blades gain gravity when they hit the floor or ceiling, and was given a "chainsaw" alt to help him climb and have melee.
Airman
Nothing at all.
Bubbleman
Something about his bubbles bouncing higher, I still wish he had sliding bubbles like megamans.
Quickman
Speed lowered, but gained an ammo bar which would give him an item that allows him to use the old "super" speed. This "super" speed works well with his ability to wall jump now, allow him to MMX walljump in a way.
Crashman
Main thing is he lost his alt and gained controllable crashbombs. They do not stun on direct hits anymore, but the blown up ones on the ground do stun. Crashman is severely tricky now and can totally catch people off guard with those mines.
Flashman
Nothing that I can remember.
Heatman
His alt was changed to a fire shield. When active he has "enker-like" armor, he will charge forward when hit, and will continue to have the "enker-like" armor during the entire tackle. Jax made this change and wanted it to be used for Heatman to get away and to charge through "buster walls."
Woodman
Nothing I can remember.
Needleman
Nothing I can remember.
Magnetman
Magnet pull changed to magnet push. The push itself will do 1 damage min or 5 damage max, so don't rely on it to kill. (Personally I wish magnet had both Push and Pull)
Geminiman
So much trouble on making the clone respawn, in general the clone would only respawn if the Geminiman who summoned it killed it. I couldn't figure it out so Geminiman was left alone.
Hardman
Haha no changes.
Topman
Buff to his spins power, a clever topman could take out a hardman.
Snakeman
Less ammo for his mainfire, but more control to his main fire. Dunno why the alt was sped up, but it was.
Sparkman
A sound change to his alt fire, his main fire gained more control to the shot by moving the charge time to AFTER the shot and not BEFORE the shot.
Shadowman
He regains ammo from throwing blades, gained a second long range blade.
Brightman
Nothing that I can recall.
Pharaohman
Nothing.
Drillman
The inventory changes by Jax fixed alot of weapon/item glitch usage for him.
Ringman
He was changed to the way the creator wanted him originally, I think.
Toadman
The ability to move after getting hit while using the main for Toad was a glitch and was removed. Because of that, he gained the ability to look around while using his main and gained more armor. Toadman also has "stun armor" during his alt jump, more explained on Stoneman.
Dustman
Nothing much, a glitch was fixed here and there with his HUD.
Diveman
Nothing much.
Skullman
He WAS changed, Jax reworked the way his runes are given so he doesn't have periods of possessing runes at the wrong times. Plainly you won't notice a difference, but you'll find his skull shield lasts shorter than before during RAGE.
Gravityman
Jax MADE by HIMSELF a ceiling walking item which works great in my opinion, its very smooth in general and works well for Gravityman.
Waveman
He regains ammo when firing his harpoons.
Stoneman
Wooo boy, this guy got a great ability this version, STUN ARMOR. This armor prevents him from being stunned at all by weapons such as Iceman's alt or skullmans buster. I believe he can still be stunned by Sparkman like weapons. Yellow devil also reworked the arc his stones travel making them more smooth in a way.
Gyroman
His gyros can now ride along the floor and ceiling, pretty damn useful.
Starman
His shield in the previous version didn't give him half armor to several of the new weapons and MM7 weapons. This was fixed and his alt was given a crap ton more stars, that are slightly weaker than the previous version.
Chargeman
The main thing for chargeman? He gets that almighty stun armor when he is using his main.
Napalmman
Nothing much.
Crystalman
Alt fire usage increased, rate of fire decreased.
Blizzardman
Nothing.
Centaurman
He has his "clop clop" sound ever so quietly going.
Flameman
His main and alt fire are not blocked by leaf shield.
Knightman
His shield was reworked a little, protects better now.
Plantman
His buster was changed, gained the ability to heal teammates in team games, except TLMS, is ALWAYS slowly healing when not in T/LMS, and his Plant Barrier was nerfed in the amount of damage it can do, thrown and when hugging. Ex. Thrown barrier before did 30, now it does 20. And he heals with his plant barrier thanks to a simple Drain rune.
Tomahawkman
His tomahawks are blue, and he fires 5 feathers, lethal at point blank.
Windman
Gyroman but with more flight speed, less control, and more power!
Yamatoman
Nothing
Freezeman
His floor shots last longer, and his ceiling shots split when they hit the ground.
Junkman
His junk wall can be punched, he can punch others like gutsman, his junk shield slowly uses ammo (this was made to prevent lag), and he restores alot less ammo from his junk. (I also like how his junk wall is constantly glowing, SWEET RAVE PARTY.)
Burstman
His alt fire now shoots straight, can trap others easier, and is harder for him to trap himself on the ceiling.
Cloudman
His alt when flying hugs the floors like snakes, less rate of fire though, and he can't fly forever anymore. (Unless you're super skilled.)
Springman
He can restore ammo sorta when firing his fist.
Slashman
Slashman lost the ability to cancel his alt by pressing his alt again, but has gain a crap ton more speed when using it. I believe he also lost some armor. With his alt and his new ability to wall jump, he can climb walls MMX like quickman, but with less control.
Shademan
Nothing much but as a quote.
"Most don't know that he can heal when hitting with his alt attack..."
Turboman
Ammo nerf plainly, and no super huge stun during his alt.
Enker
Nothing much.
Punk
His alt can be cancel, use this to punk the others into thinking you're about to charge em.
Ballade
Lost the "boost" jump from his alt, but gained a higher jump. He also gained more ammo and can fire 6 crackers instead of only 4.
Quint
His buster spreads slightly and is slightly faster. His alt his sakugarne now makes him go straight to the ground, he also gained more forward momentum when pogoing.
Roll
This class needs to be made.
Dr. Wily
Reworked entirely
Skullsuit: Mainfire is a homing shot that does less than dive missile, an alt fire with I BELIEVE damages of 30 red, 20 yellow, 15 green, and 10 no ammo. (He used to have butt rockets which were the best thing over.)
Capsule: Obviously has flight, lasts short, fires randomly, an ice shot, a fire shot, and a electric shot. The fire, yes, can kill them, it used to do more damage which result in more "self kills" but was weakened. So yeah, not a glitch.
FootForm: Only has the homing buster of the suit, which is the same power as the suits.
I might have forgot something, but gimme a break there were A LOT of changes. Jax changed so many core things that greatly helped with a lot of things, such as improve the responses of weapons. If I missed something, tell me, cause I probably did. Also as well, excuse my grammar.