TBH, It shouldn't have that added effect at all. >_> RDM's and BLM's equivalent don't cost them anything extra, and BLM is beastly when it comes to MP restoring.
Overall, SMN is in a good spot, but there are some fine-tuning that really should be looked at. I've already listed my complains, and still my list grows with nitpicking.
Such as Crag Throw should really inflict Slow II
Heavenward Howl should really just give endrain, Give Diabolos Enaspir, and each avatar their own element.
Lunar Roar should remove more than just 2 buffs, up to like 5 depend on SMN skill, and give a notice of how many are removed
Noctoshield should be a higher Phalanx mod
Diamond Storm should be a Higher EVA Down based off of when RDM gets distract II
Ecliptic Growl/Howl Should have higher base stats 90+
Blindside/Regal Gash should be looked at for being Level 99 abilities
Carbuncle/Cait Sith Should be made to not suck for being the only offensive Light Avatars....
The list goes on.
Have they done good for SMN, yes. But for not being 1 of the 7 high demand jobs, it's frustrating when you want to play SMN, but some things fall way shorter than they should.