I really don't see any real down side with the damage reduction. if you're using an avatar for farming and you have favor up, then you're going to benefit from the decreased perpetuation cost more than you would from 15% more damage.
In situations where you actually do require the full damage of your pacts, you're focusing on doing damage which means you shouldn't be trying to be the buffer and the DD at the same time. Just don't use favor when you need full damage. The ability clearly supports two different roles or modes of play, so you need to switch back and forth, not try to do and use everything in one stance.
I mostly agree with this. Still iffy about the damage reduction but I can see why it is that way now.
This is SMN's new stance system, if we want to think of it like that. So, we have two stances:
Traditional mode: For the SMN who prefers the summon/BP/release method. Don't really have to worry about -perp, since you won't have your avatar out more than 30 seconds anyway. This is for the summoner who just focuses on warding, DDing, and spot curing here and there, resting in the meantime.
Favor mode: For the SMN who prefers to keep one avatar out as long as possible. Support and/or healing take the forefront and DDing takes a backseat. Get up whatever wards you need beforehand, and then pick an avatar/favor of the party's choice. With a decent -perp set plus the -2 from the ability, all your avatars should be either very low cost, free, or you should be getting MP back with them out. Also, there should be either a BRD and COR giving you another form of Refresh, and hopefully you're subbing SCH for Sublimation. Add Elemental Siphon on top of that and you shouldn't have any MP problems.
(Note that I'm listing all of this from a party perspective, mainly endgame levels.)
So, we effectively got a stance system of our very own this update. Is it welcome and worth it? Time will tell, but right now I say yes.