Was this point totally forgotten? it would seem that despite not being a humongous buff it is indeed a notable buff that blizz is aiming at making arms perform more up to par with where a hybrid should ideally be- Hopefully Blizz manages to continue buffing arms until it is appropriate for pve dps without causing other issues.

Yeah, instead of a 30% buff to Overpower (if you do everything right) it's now a 30% buff to Mortal Strike, Overpower, Slam, and Execute that you'll put up effortlessly.

And allowing haste to affect Deep Wounds A) isn't an Arms buff, unless Fury stopped speccing into it while I wasn't looking (which is possible) and B) would make it the only crit-DoT ability in the game that paid attention to haste once it was produced. Deep Wounds already scales with haste; more haste = more rage (= more special attacks) and more auto attacks. More attacks = more crits = more Deep Wounds procs.

Making Rend scale with haste would run the risk of Fury stance-twisting to use it; Rend has perenially been a minor (theoretical) DPS increase if you could time your stance dance correctly, and haste is already fairly close to hit for fury. Which doesn't address the boost you'd give to Arms for AoE, a problem even if you added the haste scaling to a deep Arms talent.