Malamasa, I doubt they will even bother to fix spirits for Summoner. As usual, and in the MOST typical ways, the developer never really bother to do anything to summoner. The fact that spirit is very weak summon, they could make it cost 1 mp per tick, and treat it similar to puppetmaster automaton or dragon wyvern with somewhat less sophisticated AI. So you can have spirit out all the time as an options. Heck they could grant summoner a new list of spells to cast based on which spirit you have out, for example: if you have air spirit - you get all the aero spells minus Aero 5, Tornado, Tornado 2 and Aeroja. But, you know, wishful thinking lol.