Probably going to switch to IF, RoP is supposedly the best talent for fire but I don't think is worth the trouble, specially when learning new fights.
there isn't a single fight in foundry you should use ROP as fire on, since the single target encounters are arcane fights.
IF is viable as arcane on all of the fights outside of gruul, where you just stand there anyway, the other fight i would consider it extremely strong for is kromog.
it can be played on all of the arcane fights however barring blackhand, but its not an immense dps loss to play IF.
the 5 fire encounters are all the same talents basically.
heavy movement, aoe.
LB-IF-kindling
you can swap kindling with meteor in some situations in this instance, but none of those situations have really shown light on heroic for me.
once you get the goren soul repository trinket your openers become consistent enough, 4 pce obviously being king of all tier right now but goren trinket does a solid job at giving you some decent openers as well.
without tier i had a 22k opener combust on thogar tonight for example, mostly due to the crit the trinket granted me, since I'm so damn low on crit thanks to mastery enchants and gems.