(view on youtube for proper annotations and info)
The major change that came in 4.1 was that Mortal Strike now refreshes Rend. This is a bigger help to the complexity of the rotation than one might think, however with the removal of re-rend'ing Arms suddenly feels very different.Rend is at the core of the mechanic that makes the class tick (no pun intended) and with the removal of it from the rotation it almost feel as if Arms has lost some of it's soul.
I have not yet had the pleasure of testing the new system in the execute phase of a fight. I really hope that this change improves the buff tending bore that preceded it in patch 4.0.6.
Even though Arms is far from the 'very challenging to play' class it used to be, it is still a ton of fun. And to new warriors out there it is at present a very appealing dps-class choice.