Maybe it is time ZOS consider how some other games handle grouping/raiding to help alleviate some of the performance issues that we are experiencing while still allowing for larger raids. Specifically I am looking at EQ, EQ2, and Vanguard. These games differentiated between groups and raids. A group consisted of up to 6 players, while raids consisted of many groups. The healing and buffing mechanics of individual abilities could be separated into those that were single target, group only, and raid. This allowed certain AOE abilities to be limited to group only while others could affect the entire raid.

If a 24 man raid consisted of 6 - 4 person groups maybe it would be possible assign certain buffs/heals to only affect the 4 man group while a limited few abilities could affect the entire raid. Worst case scenario all abilities of these types would be group only. This would potentially still allow for larger raid sizes as far as the UI would allow it while removing the smart healing calculations an now that logic would be dictated by who was in the same group tile as the person casting it. Synergies would also be well advised to follow these rules.

As far as single target buffs/heals maybe it is time that the tab targeting system went to a hard tab target for defensive abilities such as these. That way certain burst heals could be hard targeted at a specific target that made no difference if that target was in your group or raid or not at all. These abilities could be cast on anyone of your alliance, your raid, or your group by targeting them and using that specific defensive ability on them. Vanguard went as far as assigning an offensive and defensive target allowing you to set the tank, or off tank, or yourself as the defensive hard target and leave it set there until you tab targeted another member of your group, raid, or alliance to switch that hard defensive target at any time you wanted. It kept offensive targeting independent of defensive targeting. Offensive targeting would be left as it is with the soft offensive target allowing for the more fps feel of fighting while healing/buffing would have its logic changed to affect a specific ally, or just the members of your group, or potentially some abilities your entire raid if possible.

Maybe that is too radical a change for this game, or maybe it is not, but with the things that are currently on the table to fix performance maybe it is time to consider other approaches that have been successful in other games to keep raid sizes larger with more limiting group only mechanics within those raids to reduce server stress.