Summoner is very simple, for a lot of people that is part of the appeal, or at least it is for me. Searing light should be used any time its up though since there really isn't much reason to hang on to it, unless you're maybe saving it for the boss. The level 86 trait does add an astral flow ability to each of your summons, and fills out the rotation a little more, but no it isn't going to turn into a 2 minute rotation that requires 36 hotkeys. Maybe I am doing it wrong but I will go ahead and say that after level 86 I only cast ruin III maybe once before the next Bahamut or Phoenix phase is up so there is not a lot of filler time after you run through your summons.