Cool idea, and I liked that the difficulty scales up because you have to manage everyone at the same time. The differentiation was maybe a bit low between the different classes -- I basically used them all in the same way, and mostly just clicked randomly for what to use on them.
Tooltips would also have been helpful; or at least having the different classes have fewer stats on them (e.g. the bard not having magic abilities and therefore no mana or whatever?), so that you have fewer things to figure out at once?