I'm probably the wrong demographic to be talking about how much they like current summoner as a Bard main but I didn't like any of the casters that much until they changed summoner in EW.
now it's the only caster I enjoy playing because it feels like an inbetween leading to red mage. Because of summoner being how it is it actually got me interested in at least leveling black mage and Picto to see what having a shit ton of cast bars can be like with a kit designed around giving small moments of movement rather than the cast bars being a window to fit into a relatively instant cast rotation.
I will say I think there needed to be more done in DT to give the class more fun additions to the rotation. I agree with a pretty popular CC named Larryzaur that they should give each demi summon more unique mechanical differences rather than just being a different design and slightly stronger than the previous demi summon till you loop back to Bahamut who is the weakest demi summon. I would have preferred seeing the other 3 ARR elemental summons finally make appearances as our level 100 ability or even the level 92 one. They could have done a lot more design wise with Shiva Ramuh and Leviathan. Shiva could have had a melee combo like Ifrit given her fight and then had one long cast that applied a DoT like frostbite. Ramuh could have had a shorter duration but focused more on landing as many casts of what I guess would be called Amethyst Catastrophe to build up stacks of Ramuh's favor which would dictate how much damage the button press would do almost like wildfire it would be best to have these on a 2 second cast time to create tension for dodging AoEs and getting more casts in. Leviathan could have had casts similar to titan as a less busy movement phase but have its favor ability apply a debuff to the enemy that increases the damage summoner deals to the enemy by 10% so they have something of a selfish buff that would slide in around the minute mark but could be moved around given how summoning works.
TL;DR
All in all I still enjoy how summoner plays but that's because I enjoyed EW summoner and I wish they'd either done more to differentiate the demi summons or given us Shiva Ramuh and Leviathan after Phoenix