Quite curious what they'll do for summoner in 5.1, obviously as others said (and they themselves lol) this 5.08 was more of a short term adjustment while the bigger changes come later (so here be the more minor, non-mechanical, part of the change). At least now I can attack something at low HP without feeling like a wet noodle without any sauce.
Probably shouldn't do this for all buffs but I thought a concept that might allow job's team buffs and still be fairly strictly balanced and not as tightly bound to "must have" lower DPS.
Sort of a concept I was thinking for the Dark Theme'd Healer Eldritch/Void Necro-like job but say for example they cast curse. Monster is inflicted with curse which increases incoming damage, up to 500 potency over Y seconds duration on an X second cooldown. As you can see it balances itself no matter 4 or 8 members as it's not % based and while it relies on allies to work well and expediently it also actually offers most of it's features back to you as well. So that has some added benefit that you might be able to get some of the skill value yourself, if the skill lasted 20 seconds in a normal party situation that curse gets eaten up in like 2.5 seconds but you're off on your own and after max duration you get up to 80% value. This is obviously not "full value" but it's a lot more potential value confirmed to yourself this way vs a normal party buff skill. And just for the sake of completing this fake skill I'd suggest that once the curse is consumed you get some sort of buff or job currency (like Dark Knight blood) to utilize for other things, in a dark healer's case this might be unlocking some oGCD heals or utility features.
While you'll lose some solo potential value (which is fine I suppose, support jobs and all) you could also have the concept applied to allied buffs too. Like Bard begins to sing a song in radius that increases everyone's damage up to X potency each. Simply adding a player cap to that would then make it under perfect control (so no difference between 4 or 8 man then), say it was like the two nearest allies are invigorated by your song gaining 50% bonus attack damage up to 600 potency for 30 seconds, when the buff is consumed add a notch to the bard's song
Changes the flavor of the skills a bit and probably some team buff like skills shouldn't follow it to keep that full team concept but I felt it might work really neatly and easily balance-able that way for some jobs. Allowing their team skills to not really encroach on their own personal DPS as much (as the first example they might find a way to consume most of that buff themselves given full duration, or they wouldn't be balanced around losing as much personal DPS as their team skill would have fixed upper limits like the bard example). Just adding a bit of consistency and expectation I think.