A single slam does more or less the same damage as an ovepower crit. Deeps wounds come for ms. Some back of the envelope math:
5 overpowers in a cs=(105% weap dmg)*5*2=1050% weapon damage IF all ops crit
4 non crit slams in a cs=(220% weap damage+slam base damage)*4=880% weapon damage+5*slam base damage
3 non crit slams 1 crit slam=1100% weapon damage + 7*slam base damage
2 non crit slams 2 crit slam=1320% weapon damage+ 9*slam base damage
Counting banner which is 20% more crit damage op will do 105*2.2=231% weapon damage
While slam does (220%+base damage)*2.2=484+2.2base damage
I think it's obvious why slam is way better during cds
Slam is better, though we cannot fit 4 slams into the CS Window, we can only fit 3.3 Slams during CS+cooldowns:
A total of 660% weapon damage + a total of 2991 bonus damage (has aprox 45% chance to crit)Costs 60 rage4 Overpower during CS+cooldowns:
A total of 1008% weapon damage (all criticals with reck+skull banner)Costs 40 rage
In a PvE situation (with PvE buffs too), Slam is better.
But unless we PvP'd on PTR we don't know how valueable the nerfed rage is.
If we're raged starved, Overpower delivers pressure while still leaving us enough rage for an extra slam outside the cooldown window. Or if we're lucky Sudden Death procs during it, and we can spend the rage we saved on a Slam.
Latest stat values are on Elistist Jerks
Wdps > Hit > Exp > Str > Haste > Crit > Mastery ~= AP > Agi
In PvE haste is slightly better than crit, while crit is clearly better than Mastery. This does not answer for PvP since we have less uptime, but gain rage from Second Wind.
E.g. I'll go haste till my rage generation feels comfortable, then Mastery to increase the chance of Sudden Death procs during cooldowns.