Punishing players for roleclaiming definitely makes this game harder for the town to win. Because only a true roleclaim will go punished (the player becoming useless to the town in the process) and it's likely that antitown players aren't going to give true roleclaims when pressed.
Although... I'm assuming giving away the name of your character will be enough to be considered a roleclaim, right? If that's the case then it at least puts antitowns into some difficulty as giving away their character means losing their abilities, but lying about their character means they could very well get caught out - there are only 35 playable characters in Brawl and there's 13 people in this game - taking into account that some chararcters in Brawl are unlikely to appear here together (eg. Samus vs Zero Suit Samus), lying about who your character is would be highly risky.
This new rule does encourage people to fear pushing for roleclaims though which I don't like, and it also makes numerous roleclaims in one day highly undesireable. On top of everything else it just makes a themed game even more complicated and confusing.
[On an unrelated note, I might be a bit slow in responses today because I have a fuckload of forms to fill in for a new job.]