1. Pup is terrible. It is the least popular job, and the least useful job. There is literally nothing in the game that pup excels at. Every single thing you could possibly do, another job can do better.
Anyone that thinks pup is the worst job in the game now, never played it back when ToAU came out... Doesn't really matter if it's the least popular job. Cor is the 2nd least popular job and it's very useful. Casting lower tier cures isn't really more mp efficient. Soulsoother doesn't have WHM AF3 pants, and it certainly won't be curing for 700-800 with cure IV. If you're getting cure VI when you're barely missing HP, don't ride light maneuvers or take off damage gauge, that way the puppet won't cure you till you're lower HP. Optic fiber will also make it cure at higher HP's in combination with damage gauge.

I don't see how casting cure IV would make PUP more popular, and I don't see how it would make it more MP efficient. That said, I wouldn't complain if they changed it, however, I doubt they will. Honestly, if people want to complain about a puppet, they should be complaining about Valoredge. Followed shortly by Sharpshot.

Valoredge does terrible damage, and it's not even useful as a "tank" as useful as those are today, since it's not capable of being cured nor does it heal itself outside of cannibal blade. Sharpshot is not as bad but it's ranged ACC leaves something to be desired, with the lack of a "Scope II" attachment. It also tends to die quickly if you can't manage to keep it out of AoE range, meaning it will rarely get a WS off before dying. Maybe if it got more than 10 TP per ranged attack it would be more useful in the fleeting moments before its untimely death.

tl;dr Soulsoother is fine these days, please complain about stuff that's actually broken with PUP.