I still think we need to define or redefine what useful utility actually is. As has been mentioned a couple of times already, defensive and "auxilary" utility is obsolete in the modern version of the game, which is why the T1 offensive utility measures up as equal to, if not more valuable than the utility that summoners provide. Gone are the days where necro single target cc and self sustain that are baked into the identity of the class matter in any way at any tier of gameplay. Same goes for conjuror's stoneskins, encounter cc, and other defensive utility. Both summoners are also suppose to have intrinsic utility via the use of a pet, which is suppose to make solo gameplay easier and allow them to "do things" that other classes can't. However, with the combination of mercs, field medic, and overall design of content, there's no real advantage having a pet - every dps class can solo equally - and heroic content is gated by mechanics that force having to bulwark and/or cure curse. The toolkit element of using different pets for different situations has also been intentionally forgotten about since many many expansions ago (scout pet all the time for everything). In essence, all that matters nowadays is damage, so any T2 class design or utility that isn't geared toward doing more damage has way less value.
With that said, summoners have always been plagued by the inherent design issues of an un-interactive/automatically controlled pet. Since the class can do 20ish% of it's damage afk, that naturally hinders the expected dps ceiling of the class. Or examined differently, lets imagine that conjuror and assassin design is kept as is, and the numbers tweaked such that they do equal damage with equal buffs. On the conjuror, the damage curve is flat, 100% at range, and requires an average of 20apm. On the assassin, the damage curve is incredibly spikey (more heavily influenced by combat conditions/mechanics and buffs), 98% melee, and requires an average of 120apm and specific coordinated burst chains. In this world, why on earth would you play, look for in a group, or bring to a raid anything but a summoner (ignoring the forced/encouraged class diversity elements of the game).
In truth, the entire combat design on live would need to be reworked to enable the class dynamics that the game is fundamentally built around, that we see in class design and in aa's that are no longer relevant today. In leu of that pipe dream, I think that summoners should just be considered dps at this point, with a high dps floor, but slightly lower ceiling than predators and sorcerers. I also think the same treatment should be applied to rogues, and to make both sub classes' self buffs more powerful, with lesser base damage on spells (this being a way to enable the high dps floor while limiting the ceiling). Keep the following unique elements of the classes - Brig (thieves guild, double up burst, and combat mit debuffs), Swash (powerful group temp buffs, aoe damage), Conjuror (consistent and reliable damage for single and aoe fights, sacrifice, shard buffs), and Necro (fd + res, reliable single target damage, heart buffs). These unique elements of the class should be powerful enough to make up for any lost dps by not having a predator or sorcerer in their spot. In doing so, offload all of the utility onto Enchanters and Bards (including the offensive utility on the T1 classes atm), and heavily buff that utility. Allow both sub classes to fulfil the powerfeed role completely. This design should also make it so that rogues and summoners will out dps predators and sorcerers if there's no bard or enchanter in group. Add a bard or enchanter, and the predators and sorcerers should pull ahead slightly, getting larger and larger as every party member approaches bis in everything.
In reading that back, I realize and stand by the idea that this balance perspective might make it so that the optimal raid only has 1 conjuror and 1 necro (and it would be important to make sure the heart and shard buffs make them worthwhile/necessary to bring), and tbh I think that's completely fine. The class strengths make them good in heroic content, and less reliant on a good group comp. I also think it's worth acknowledging that stat mechanics are designed such that a well geared summoner will do 2x+ the damage of a mediocre geared predator/sorcerer, even in the best group setup. It's also worth noting that none of this addresses an underlying issue with burst damage and how everything has to be balanced around RU, which is a whole other conversation but a significant factor/impact on trying to define summoner's role as dps.
