My problem with the Summoner is that he (or she, it's Lohse) deals damage only from turn 2. In most fights it's difficult to close the gap to other classes. My only wish were that totems would shoot immediately after being planted.
Of course you can summon pre-fight but that is only viable for me if I could notice the fight in advance the first time, so not for ambushes. It's lame to reload and prepare.