[Poruku]

There already exists some skills in the game which have special bonuses when "X is both your main and sub class". I think those should simply be much more common. If mono aquamancer had like 2 other skills that got way stronger it would start being a contender for that monoclassing turn 1 call storm dream.

I think making it just one bonus would be too limiting. And the technology is already there!

Also, specialization should give other buffs than skill pool size: a monoclasser already has a limited amount of skills, what they need is more power. Like, +1 rank to all skills as if you had a spirit for each? Sounds strong but makes sense