It sounds good in theory, in practicality however it's bad. The minigame you speak of will cost you 60 Rage for example.
While numbers can be tweaked I'll remind you that it took four expansions and two patches before Arms numbers were tweaked to a degree where it became viable. Numbers are a deal of the class fantasy and while it might technically be better than Legion, the reality is that it feels like a wet noodle and fails to fulfill the class fantasy of the consumate weapon master.
And our Mastery only affects two abilities. Both expensive and one conditional. The datamimed version it was an extra hit and five Rage was so much better and more fitting.
Also the "Coming Soon" talent turned out to be Impending Victory. Which I"m so, so about, because a weapon conditional would be bad "So for PvP I'll mog a mace and for PvE an axe/polearm."
This would put a financial burden on Arms that no other spec has and imagine if it was tied to the original weapon type.