Sajakain, I am not convinced at all by your test. To be honest, I simply doubt that 45 ArP can increase your DPS by 200.
Looking at the numbers you provided, your execute damage % jumped from 9.8% to 13.3%, while your MS damage stayed pretty much the same.
Since I have no reason to believe that execute benefits more from armor penetration than mortal strike, I simply believe that you had more sudden death procs on the second test.
The decrease in slam damage also points in this direction, since more sudden death procs would lead to less free GCD to fill up with slam.
5 minutes is probably not enough time to see a real difference, too prone to RNG.
I would also agree with you. Something I have not posted: I did re-socket ArP. Guess what happened? DPS went down to 2300 - 2400. So while ArP may be nice, and could help, slightly at most, it's not the stat to go for. SD did proc more on the 2nd test, as the results show.
However, I would say a 5 minute fight would be as good as a 10 minute fight, going strictly off the Battle Shout CD. The only difference is time. You're still going to do the same rotation, just twice over. The only other difference that would come into play is the chance for more procs.
The question that remains, though, is how are some people putting out 3500 DPS when at best a handful of us can only put out, at best, 2500 - 2800? Is it just they're getting extremely lucky on procs? Or is it something else?