On some of the missions where it is four-on-one against a villain, I've noticed that now I'm getting a "free talent point" if I reach the gold level. Which of the heroes gets this talent point?
All of them, maybe. I think.
Yes, that's the general idea. That you're doing the extra missions to get the extra bonuses the characters you use get for the missions (like the "Get a levelup" bonuses, for example).
The original (unmodified) game didn't give any talent point for the gold level, did it? It's been awhile since I played an unmodded game, but I don't think you got any reward for any level.
yes it did.