Every other summoner I've come across seems to have a different opinion on how effective they feel as damage dealers. Some say they're consistently on top of DPS, some say they're on the bottom. It boils down to skill (keeping DoTs up for maximum time before recast, fester usage timed with aetherflow being back up, etc)

I agree with you and would like to see summoner stronger, cooler looking egis (11 had perfect sizing not sure what was wrong with that) give fewer DoTs but higher potency (lookin at you Miasma 2) maybe give Ruin a chance to randomly put one of your DoTs on a target, or a chance to refresh one, and have the pets have completely different moves.

How about one that has a focus on single target, one that has multiple AoEs, one that applies it's own DoTs, etc, not they all have the exact same moves but pallet swapped and slightly different potency

When ifrit is out, bio has a chance to light them on fire and add another DoT, when titan is up miasma has a chance to reduce enemy damage by x% (give a reason to use him during bosses?) when garuda is out ruin has a chance to do AoE damage (we're SORELY lacking in AoE and shadowflare aint gonna cut it), maybe ramuh can have several debuffs

Just SOMETHING that distinguishes the class as a summoner, and makes the different summons viable. With the current format they can't really add more summons, they'll just be pallat swaps