TaranTheWanderer
Legend
Not that I necessarily agree with making double concentration a Feat, but why the fear of letting human variants get it at first level? That says to me that you think it's more powerful than other feats.
Nah, I just noticed from the thread that lots of people feel double concentration is too powerful and, if so, doing it this way might be a balancing point. And there is precedent for feats needing a prerequisite so it doesn't add an extra rule or anything.
Depending on how overpowered you think a feat like this would be, you can make the prerequisite (either another feat, or a minimum stat or proficiency)as easy or restrictive as you like. Or don't have a prerequisite at all.
People will be less likely to take the feat if they have to take 'linguist' (because very few people would voluntarily take that feat) but more likely to pick it up if they have to take Warcaster (because they were going to take Warcaster anyways)