I doubt we actually disagree that much. There were plenty of fights where summoning doesn't instantly solve your woes - in fact, I think Last Stand might be more of an issue because that bypasses a lot of the fights where summoning won't save you.
I also play without rest unless I absolutely have to rest, meaning I basically only summon in important fights.
As well, I do think Deskari is kind of a disingenuous example, because 1) it happens at a point where you are laughably OP and pupstomping everything, 2) it is easily the most disappointing fight of the entire game in opinion. Just shit design. Deskari has way too few defenses and way too few relevant attacks (which he won't get off because he is so easily killed). He should spawn a gazillion tough swarms and be undamagable until they are dealt with or something similar on Unfair.
There are two reasons I think you find the game so exploitable: your builds are better than mine, and you play without double damage. At least, until level 17-18 I had a few fights that were balls hard, and lots more where I had to pay attention, I couldn't just auto through them.
You say the AI is horrible, but it's all perspective, isn't it? After Kingmaker I thought maybe with all the shit going on in PF and all the power and synergy available to the player, maybe it is just impossible to create compelling gameplay. Especially considering 90% of the player-base thinks the game is nigh unbeatable on Core. I think WotR proves that there were actually venues for them to increase difficulty despite that. It still has a lot of the unavoidable problems that the system complexity introduces, but it nukes enough of them that I'm having a blast.
A lot of people say they would love an SCS for PF, and while I obviously agree in principle, this point itself highlights why these issue exist in Pathfinder: SCS is one of the most complex, layered and iterated upon mods in RPG history - maybe *the* deepest AI-scripting in RPG history *period* - and it "only" had to account for basic auto-attacking, a handful of defensive spells and the spell defenses vs. spell strip minigame.
Meanwhile, a similar mod (or developer implemented AI) would have so much fucking crazy shit to account for - and if you "overaccount", you could easily end up with unfun fights that required specific builds - meaning there would be an insanely heavy testing-and-iteration burden on a project - fan made or otherwise - that attempted to upgrade the AI significantly.
Now you're gonna say "how about they just do basic shit like bosses don't target summons and we'll get to the complicated stuff later," but considering a ton of much more basic shit still doesn't work as it should in these games (we're talking entire build paths or something like enlarging spells being hell to use with mounts, something almost every player is going to encounter yet which is still an issue), I think it's wholly unreasonable to expect better encounter and enemy design than what we have in WotR - it surpasses my expectations.
In other words, you could call the AI terrible in isolation. But I find discussions such as these become misleading very fast without context.