I may not be completely updated on how much healing bard puts out post buff a while ago but I struggle to imagine bards becoming overpowered if they had a res.
This could be a product of bard being preaty underpowered in the past and therefore less experianced players playing them but the class still appears to me to feel a little overshadowed by musket in terms of healing. I don’t have numbers on this so I could be vastly incorrect but bard certainly feels like it puts out less healing. If I heal most bosses in the game correctly as a musket in a level 15 shard, my cure wounds orbs is not required to keep the tank alive because my passive healing orbs are more than enough. It just feels like with bard your heal burst is a required part of your rotation to constantly fight to keep your tank in the green whereas with musket you put out so much passive healing you can usually save your the best heal orb exclusively as a backup heal for mistakes.
On the note of individual damage, bard does more damage which in group content is fairly insignificant when compared to the numbers your dps are pulling anyways.
The one main advantage bard has which I will admit is a preaty huge deal is their ult. Being able to buff the damage your dps are doing is paramount to basically everything else besides the bare minimum to keep your tank alive. This is the main reason I would imagine bard still probably sees play at high levels.
Realistically though I don’t think giving bard a res would change anything about their niches. It would take away only one of many utilities musket has. Musky still has a turret, leather armor, an ability to intentionally pull agro, long ranged healing, and requires significantly less focus and micro. For example on raids, assuming you are balancing the content for parties of people who actually have to do boss mechanics, muskys can still
Tank ads on boss 2 of gc
Pull clones on boss 4 of gc
Solo circles on boss 5 of gc
Shield all dps on shard jump on boss 1 of citidel
Tank ads on boss 3 of citidel
Tank ads and block orbs with their turret on boss 4 of citidel
Some of these are less useful than others but some of these fights would be much harder without an ability to healer tank or exploit a turret.
Basically I feel like bard is in a similar place as warrior where theoretically its better in end game when survivability becomes more trivial in favor of better dps buff/agro pull but it happens so late in end game that you rarely see it actually see play outside of content done by players who have far exceeded the intended experiance level required for it. I agree bard is in a okay place, I’m starting to see more of them pop up, but I think a res would push it closer to the line instead of over the top