Well, i might as well post some map feedback i've collected.
GVH22 has some trouble with camping spots inside the graves, in particular the large one without the marine stabbed by the sword. Altrough the ghouls can approach from the teleporter, it still may be hard to impossible to counter them. Especially if the ENTIRE team likes to camp there, and the halls in the graveyard are somewhat small, too. The doors even more, its hard to fit a Jitterskull trough there, if i try to nab someone going trough, they fit in, i get stuck on door sides, ussally.
GVH23 does well so far, some like to camp in the room with the switch that can turn off the lights temporarely. Nothing impossible. Not sure what to think of GVH24 other then that the textures could have looked better. But i guess thats standard doom textures made blue. :P
As for GVH25, it could use some major tweaks. Perhaps more cover, but more importantly, more then one tunnel leading from one to the other section. Currently there's 3 big chunks of map connected in a row by tunnels, having 2 or 3 tunnels connect to each chunk of map would do in order to get past humans guarding one entrance and attacking them from behind. Some (especially Mobius) find the ceiling rather low for Sjas, too. And it could perhaps use more cover, in some spots, to not get sniped by a marine/hunter on the other side of the map, atleast.
And GVH26, last time i seen a game, humans dominated. Atleast they're running around more instead of using said camping spot, its alot better now.
As for GVh27, i think you kinda ruined it by completely removing all cover near the pointy end of the ship. Ghouls will heavily reduced in numbers just trying to get there, especially if the entire human team camps there. Perhaps add where that small gap with the fire barrel is a larger gap, with a ladder, containing some cargo? A bit of cover for those who go down, perhaps. Or add more boxes, it can hardly be Jitterrape if you added less then originally where.
I cant think of any feedback for GVH28 other then that some people are reporting that there are a few HOM's left. GVH29 is pretty interesting at large scale games, but marines with accurate shots will destroy any ghoul rather easily. Cyborgs can jump onto the... higher bars that connect the poles around the giant laser shooting pillar, and actually stand on it, standing out of Jitter's reach by being on this bridge thing. Oh well, if your faced against projectile classes and are good at dodging, it might be more fair then meets the eye. Cant think of any feedback at all for GVH30, its... normal.
Oh, and in GVH25, there's also a weird HOM effect Mobius found, i made a screenshot of it since he has trouble doing so. :P

I'm merely guessing some of the map feedback is a tad... repetetive. :P
When it comes to classes, many find Frostbite rather weak, a buff would be of use. And seems Santa's star launcher is rather effective if you use it close range, it may be a bit cruel on the ghouls, but they didnt get me that often with that trick. Hmm... Unless it damages the user now too. :P
Edit: The ship map doesnt seem to lag me. And the new sea is much better too. I only get lag when frostbite uses his breath in that certain location, did you fix that yet?