Thats something I've been pondering. What purpose was Hydaelyn summoned for anyways? If it was just to defeat Zodiark then she should've dissapeared afterwards, no? Did she also get directives to guard against his return? If so, she wasn't set up very well, considering her semi-hand-off methods and apparent weakness. I'm also starting to lean on the side that summoning such primals came with unexpected aspects, some of which we're still experiencing the consequences of.
Something possibly worth pointing out is, that the alternative you are arguing for, may be worse in effect than the original theory.
You imply, that all political situations a WoL takes place in are Ascian made. That would imply that most of the major issues in the world are caused and solved by larger powers, manipulating the mortal races semi-directly (in the case of Ascians) or indirectly (blessing of light).
Not saying this is incorrect, just that it some ways worse, and possibly still reason enough to hate both sides. Fighting determinism is a common enough theme in jrpgs afterall.