It was with Stormblood, and it's the reason I'm always in absolute disbelief when people say SB was peak Summoner. Does no one else remember what a disaster trying to get Garuda to contagion before the demi window was? God what an awful experience. Either it took so long you started drifting from Trick and other buffs or you'd just ghost it because the demi registered first. There was no good solution and it would only be infinitely worse in the current meta.
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While its true that there is probably some shenanigans with having multiple pets, this is only true for demi-summoning itself. There was zero reason for gem summons to be tied to the demi system though. It would have worked identical to how it is now if the primal summon was just a VFX that had no impact on Carbuncle at all. In fact it would be significantly better because there wouldn't be a delay on damage caused by the entity spawning in before it can attack. Just an utterly absurd decision. Anyone actually playing Summoner could tell within 10 seconds what an awful idea that was even with the pet being made damn near vestigial but they did it anyways.
Honestly I have 0 faith in Dawntrail fixing anything for Summoner. I've been saying the demi summon mechanic is awful since it came out in Stormblood, and yet the dev team has doubled down on it to the exclusion of everything else in the jobs kit. It's just stripping everything out while ignoring the problems this one mechanic has infested the job with, and even with all of that it still hasn't fixed anything. They'll probably just delete the rat and happily exclaim they finally fixed ghosting without having fixed anything at all.
If I sound bitter, it's because I am. I've given them 3 expansions to solve the root problem and they've not only ignored it every single time, they've also just doubled down and made it worse every single time too.