Impact of Characters with Resistances

[Regicide]

This would seem to take some of the game away from the players. It should be up to them to determine that they're going up against, like say undead, from the adventure and gear for it, with say, anti-necrotic effects, not the other way around.

 

[Ulthwithian]

I don't think that's quite the same thing. I think the OP was pointing to a decision that the player made about his character in the past (i.e., race), and how to highlight it without going overboard.

Also, while I can see how a player-driven campaign could work as you suggest, my experience in RPGs has been that very few campaigns are actually run that way. As such, the more traditional GM-driven story (with player input) would probably be better as the default setting in which to base discussions.