From 2.0-4.55, I was more of a Healer, but Summoner was my go-to DPS. I'm now all-in on Dancer (which doesn't have anything to do with the way the job plays), and my experience with Summoner in 5.0 isn't as developed, so take what I have to say with a grain of salt.

The change from Egi Assaults being oGCD to GCD is a really nice change in my opinion. Before that, it felt like oGCD weaving hell, and even feels a little intense still. I imagine people who are spending all their time into Summoner are probably enjoying the busy rotation because it keeps you invested, but it would be nice if it was a tad bit more forgiving.

My biggest complain though is how disjointed it feels. You have five main categories of DPS tools: Ruin + Ruin II/IV Weaving, DoT Management, Aetherflow Actions (ED/ES + Fester/Painflare), Egi Assaults, and your Trance/Summoning Rotation. Most of these feel very disconnected, like your Aetherflow actions used to be a central component of the Summoner's kit, but now that it has nothing to do with the summoning rotation, it just feels like extra busy work that has nothing to do with the rest of our tools anymore, except DoTs and Fester. The Egi Assaults also feel like they're just kinda there, as well.

I want to see more cohesion within the kit so it's less all over the place and more focused. Not everything needs to all flow together in one giant machine. The DoTs and Tri-Disaster, for example, are fine as they are. I think it may be time to drop Aetherflow altogether since it's basically a vestigial limb at this point. I'd also be kinda into the idea of Egi Assaults replacing Ruin spells while your pet is summoned.

Also, could we maybe get some attacks from other primals? Like I'm not expecting us to summon egis or demis of primals like Ravana, Bismarck, or others, but what about oGCD attacks where we briefly summon those Primals in partial form for their signature attacks before they disappear? We could even have Aetherpact Change to Lakshmi's Alluring Embrace. Same effect, but more themed around actual summoning.

Again, I definitely have less experience with Summoner now more than ever, so my opinions aren't as useful as someone who's been maining it.