We only have public information to go off of, but for Summoner - if you are familiar with Aion, I get the impression that Yoshi-P is mostly copying the Spiritmaster.
I'm just making an educated guess, but since it's a debuff/summoner (like Spiritmaster), uses a book, same battle animation, similar looking summons, it seems that is his 'inspiration'.
Scholar was just revealed but they described it as a healer which would be more HoT focused.
Bard was basically an Archer DPS in 1.23, with a few support spells sloppily thrown in - hoping it will be changed for ARR.
Edited, Jun 17th 2013 9:45pm by Killua125