[Shujin]

Samba of Strength, without performer, gives you +2str +2ski +10 SWA +10 Critical in a range of 5. for 3 base rounds without instrument effects. +15 crit for 2 attacks with Performer. and whatever duration Performer RNG grants you. I think the range argument is fine but you can boost it with volume up, and in some cases even play the song passively for no momentum cost. It certainly has a bit more than just "+5 swa"

I agree that some buffs, when compared with each other will be seen that way. But which of these buffs are actually used in battle, actively as part of a person's strategy?
Many people agree that Performer is the worst class in the game, because it barely brings any Damage, which leads to the conclusion that even those buffs on themselves are not able to carry the weight of someone else just doing their thing. I do however agree that its probably from a buff standpoint is the closest to Invigorate. I do still think though, it does the job better even if only slightly. The being able to cast it for free option, is really valuable. but then again, who would use that on Samba of strength instead of Dawr of Defense? I think the latter is actually a really good buff now with the recent buffs to it.

so I do not think its the right way to look at it to compare underperforming buffs with one another, but see if we could attach some other interesting things to them other than just raw SWA, as kunai suggests and FP regen would be not bad. Also to play devil's advocate, there are plenty of buffs that are currently in the game that have certainly a stronger buff and usually do something in addition:
Brine Blade(if we talk raw damage, its always way better, assuming basic attacks.)
Ignite Power(40+SWA might be tile based, but its not that hard to set up to fully benefit from it, and is more or less actually free as you set them up by the by.)
Salamander Sword (up to 100 Power, granted only for yourself, but certainly way more potent, with 0 direct momentum costs)
Absolute Death: 0M +10 SWA buff, for a bit of FP costs, plus some extra chip damage in AoE.
All elemental impact Mage Buffs, cast by a mage, will outperform Invigorate many times thanks to the stats+elemental damage, assuming someone uses any form of basic attacks.+points for evoker. Also that one got nerfed alot with the mage changes. With ruler thats however a very great buffer.
Verglas bear stance: (passive easy build up +30 SWA and +30% Crit Damage.)
Titangale: (okay this one has a little more difficult condition but can go anywhere up to 120 SWA buff for 5 rounds. This one I admit is probably not fair to count in)
Blackdrain: Passively +10SWA for stuff you are likely to do anyway, and also reduces enemy SWA
Engineers Flamethrower: +15 power 7 rounds. also grants flamethrower, but no one cares about that part. single target.

There are a couple more, but I argue that a big majority of buff exceed 5SWA for whatever amount of rounds. Most buffs have something going for it, but many of them are actually stronger and cost no momentum at all. I am obviously not trying to say, that these direct buffs should be more powerful than these above. But I think there is nothing wrong with cranking them up a tiny bit.
the only 3 buffs that really play in the same category are "Crack Joints", "Sharpen" and "Invigorate". And I think all of those aren't good when used for 3M (crack joints has a 1M option, making it cool again. and more useable.), and you really just use them if you have literally nothing else to do. My boy sharpen, should just become what it was pre nerf. Invigorate, in my honest opinion, just deserves to be a little better, given it comes from a Buffing archetype.

I do not think personally it be game breaking if it was +10SWA, If anything I just think a raw SWA bonus is just boring, and I personally would think that something next to the SWA bonus, whatever it ends up being, might be cool.

but who knows what Dev is cooking up as the next class for Curate. part of me is hoping its a more dedicated Enchanter/Buffer. lemme cope!