CoV has more unique maps/missions than CoH. Right away, before you even hit lvl 6, you've already seen three different (and completely unique to their respective missions) maps. All three of them are outdoors. One is fighting snakes, saving arachnos grunts who then end up fighting with you. Another is killing longbow, and its a short mission (first mission you ever get) and another is planting explosives on Arachnos transport vehicles (you kind of work both for and against arachnos at different times in the game... it's pretty cool, actually).
Sadly, later on, you do get into a lot of office-buildings, warehouses and caves/bunkers. BUT... you still get the odd bank hiest/casino robbery/ misc. robbery which always has a unique map. You get a few very cool unique missions like where you plant the Outbreak virus in Paragon city, and you have a shitton of Longbow to fight (that mission can take like 40 minutes, and pretty-much guarantees you a level), or where you visit a dry-dock and fight ghost-pirates (awesome mission) or where you have to kidnap this chick from lonbow and you have to go into skyway city to do it, so you're fighting in a kind of instanced Skyway zone, which is really cool.
All of this (and tons I've forgotten to mention) before lvl 15.
I7 (when it FINALLY goes live) will also bring some new powersets. From what I remember it will bring Thugs Masterminds, Electric Brutes and... something else. I can't remember what else.
If you want a brief description of the different archetypes, read on...
Brute: Like a Tanker in City of Heroes, these guys are meant to take hits. However, Tankers had insanely high defense, but couldn't really dish out the damage very well. Brutes are a much more balanced AT... their defense is the best out of the 5 CoV ATs, but their damage doesn't suffer the way a Tanker's does. They get an inherent ability called 'fury' which builds up as you fight, causing you to become more damaging and more accurate, the longer you fight. The 'fury meter' drops very quickly when you're not fighting, so the ideal is to just run from fight to fight, constantly in the thick of things, and when you get that fury meter up to full, you're one-shotting everything in your path.
Stalker: Many people equate this at to Scrappers from CoV... but I disagree. Whereas Scrappers had almost as good defense as Tankers, Stalkers are - what I like to call - Glass Knuckles. They are assassins. They sneak in, completely invisible, and do crazy damage while hidden with their 'Assassin's Strike' ability, which - when slotted properly - can one-shot an orange boss. However, they CANNOT take hits. If they get aggro, they die... fast. They're a good addition to a team, as boss-killers, but they need support... because once that boss is dead, they're getting their asses kicked.
Dominators: Think of a Controller/Blaster hybrid... and that's a Dominator. Your primary set is comprised of holds, immobalizes, stuns, sleeps and debuffs... just like a Controller in City of Heroes. However, Controllers in CoH had a healing/defender secondary, which was pretty weak. Corrupters get blasts. Remember how potent Fire Blasters were in CoH? Well Imagine running into a group, holding all of them, summoning a pet to run and attack them, then popping a Rain of Fire on their heads. Throw in the fact that Dominators get an inherent 'Domination' ability (the meter builds and when it's full you can turn it on to do double-damage, and increase the accuracy/recharge of your holds/immobs/etc... AND it fully replenishes your endurance).
Corrupter: Think the opposite of a Defender. Defenders had heals primarily, which were very strong, and weak blasts as a secondary. A Corrupter is more of a Blaster with heals. They do some of the highest damage in the game, and right now there is no more damaging at in EITHER game than a Dark/Fire Corrupter... these guys are MOB KILLERS. Being the only pseudo-support AT they become very popular in teams, but they can probably solo the second-easiest of any other AT, because of how much damage they can do, while still being able to heal themselves.
Finally: Masterminds. The most unique AT in City of Villains. Remember how much fun pets were - for Controllers - in City of Heroes? Well a Mastermind gets a pet at LEVEL 1!! Then he gets a second pet at lvl 6... a third at lvl 12... a fourth at lvl 18... and a fifth pet at lvl 26! That's right, you get a total of 3 tier-one pets (zombies, battle bots, ninjas, mercs) two tier-two pets (Dark Knights, Protector Bots, Genin, Field Operatives) and one VERY powerful tier-3 pet (Grave Knight, Assault Bot, Demon/Oni, Tactical Operative). You get upgrades for your pets to give them new abilities and powers, and as a secondary - for a mastermind - you get a support ability (traps, force fields, dark miasma, poisons, etc). These are the most fun AT to play, in my opinion. You are typically so busy controlling your pets, at higher levels, that you will basically just stand back behind the fight and coordinate, maybe running in once or twice to buff your pets/team or heal... then running back again. While most people would frown upon such seeming inactivity, everyone in CoV understands just how busy a Mastermind is... so it is very common to see the mastermind apparantly just standing in one spot doing nothing. The reality is he is controlling each and every one of his pets, telling them where to go, who to attack, what stance to be in...etc. They're a very challenging AT, but the reward comes in how versatile they are. A mastermind is ALWAYS a valuable addition to ANY team. The pets do crazy-good damage, and can become convenient meat-shields. Masterminds, however, also have the easiest solo careers in the whole game. They are - after all - a one-man army.
If you're looking for a good solo character, go with Masterminds. If team-play is more your style, Dominators are a ton of fun to play, and they do need teams a lot of the time. For a good mix of team and solo, corrupters are great, and when you want to team up as a corrupter, you never have to look very long for a good team. You are in demand! Brutes are - honestly - in need of some tweaking... their defense needs to be kicked-up, and they need to have some endurance-incentives, as every Brute I have ever seen is tired after a single fight (they run so many toggles, that you can just stand there and watch their end drop to nothing in a few seconds). Stalkers are very cool, but the main reason to level a stalker is for PVP. There is very little that can compete with a Stalker in PVP. They are - after all - assassins... single-target killers... and when played properly, they can drop a hero in a PVP zone in a matter of seconds.
