I certainly wouldn't mind having the ability to make more barrels, but I kind of like not worrying about control, and I can see how even better kiting might be seen as OP.
I agree about Refreshment. Pandas have some nice passives, but that isn't one of them.
I'd personally like some kind of damage bonus for Bubble Trouble when targeting the barrel (and likewise Light My Fire). Both of those spells seem kind of underwhelming, but almost every panda build is forced into taking one or the other just to add the 3ap spell slot. I'm not sure what I'd change, though. Maybe change the Flaming state on LMF — it just doesn't fit with the long-range fire play style much, and if you're a tank build, Six Roses is just better.