Firstly I want to preface that this is strictly from a non cp bg perspective.
I think with the 20 second single target dot timers, way of fire should no longer proc on every tick of a weapon ability dot.
You are basically giving any of those dots 1-1.5k extra damage per tick, which way outperforms most dot proc sets in the game.
On top of that, beacuse the set itself is not a dot, you cant even purge it, as weapon dot can be reapplied right away.
This is the most egregious with masters dual wield and rending basically creating a 4k+ ticking dot that you can just not get rid of, even if you have some kind of purge.
In no cp this can easily eat up most of your healing, especially when combined with a couple other dots to moot.
While in cp pvp dot spam is not an issue, in bgs without healing cps, combat medic passive and less sustain this is really an issue right now.