He's out on their test server, slated to (likely) be released Thursday or Friday (probably Friday, Thursday patches are rare as fuck, especially when they're releasing a new hero). His powers look pretty neat. A variety of ranged powers using a bunch of different weapons and some melee abilities focusing on his metal arm. Nothing tremendously special except for the ultimate which is cool as fuck. Basically Winter Soldier jumps out like he's just out of your monitor, presumably into some kind of attack aircraft and your screen basically acts like a turret for the duration of the ultimate. Cool shit.
Also coming in the patch is a fairly significant buff to Captain America, who has been a pretty low tier end game character for a long time now. The addition of hp regen was probably enough to get him into the middle of the pack, but the rest of the changes will probably bring him in line with the other heroes they've been fixing lately. They've had a very good design philosophy with this stuff lately, namely not nerfing the top tier people, but just finding ways to empower existing heroes. They've done a fairly poor job of prioritizing who needed empowerment first, but at this point they're basically done buffing everyone up. These days most of the characters that still need attention need tweaks rather than reworks.
The voice work for a lot of Marvel Heroes is actually well done, with the only character getting unanimous bad lip service being Storm. The star of the show is the one-liners that have a chance of getting triggered whenever you pass another hero, with the majority of the banter being entertaining, or at least fitting with the setting well. But since it's an ARPG, voice work is just icing on the cake. You aren't going to be hearing Hayter talk all that much unless you're in a player hub/public event/challenge zone, other than some one-liners after defeating bosses and random henchmen.