Tabula Rasa & City of Villains
Tabula Rasa has undergone extensive changes since the last show, focusing less on instances and more on changing the persistent state of the server. This is a fancy way of saying that players and AI compete for territory, with the more territory that's held meaning more advantages for the winning side.
The AI is very active in the game, with NPCs going after objectives on their own. These objectives are rather involved as well - the player can choose to isolate one by taking down its defenses, or go straight at it if he feels he can muscle through.
Though dubbing itself a first-person shooter style MMO, Tabula Rasa is still more RPG than action game, with the results of combat being decided by dice rolls. Player actions, movement and weapon choice of course have effects on the rolls, but this isn't World War II Online or PlanetSide where it's all in the hands of the player. Still, from the demo it actually feels as if the game has struck a good balance and shouldn't alienate all but the hardcore shooter fans.
City of Villains
City of Villains is City of Heroes, but now you play a villain instead of a hero. It takes place not in Paragon City but in the Rogue Isles, though NPC heroes from CoH will be spotted in CoV, particularly in some missions.
The game will have 7 PvE zones and 4 PvP zones - which obviously means that PvP is being integrated from the start, though we doubt that this means cross-over CoH/CoV PvP. Though it naturally bears a strong gameplay resemblance to City of Heroes, City of Villains has a different style. Players don't fight crime, they make crime. The Rogue Isles are ruled by a mysterious supervillain who encourages chaos and evil and all sorts of nasty stuff, to separate the strong from the weak. It's not complete chaos, of course, but certainly it helps to be on your toes a lot more. Whereas City of Heroes had the player stopping random crimes on the street, he will be committing them in City of Villains.
CoV uses the same engine as City of Heroes but looks crisper and more refined. The developers boasted of expanded character customization options, both gameplay and appearance.