Hi ! I didn't find any topic discussing this, so...
I found strange that some spells can only be cast as overland spells. A good example is 'stoneskin'. I don't see any reason to allow casters to use it while in tactical battle to give a one-time advantage. IMHO This would favour magical elements where damage spells and debuff spells are in use (death and fire).
Another thing is (I don't know if it is a bug), but I noticed some of my casters got spells more than once (the spell icon in their profile appears twice). Is that intended ? I don't know.
Saved for the list of spells in the help section of the game, I find difficult to know what I can expect to get when selecting a more advanced level in magic. The tooltip is helpful, but I was wondering if it was totally random or if the spells I would get are the ones mentioned in the tooltip?