So, for me Thrash is hitting for around 1400 on a critical hit and 800ish on the DoT (450 per tick, critical). Not half bad all things considered.
Took some fiddling, but I managed to work out a good aoe tanking attack rotation macro as well.
#showtooltip
/script UIErrorsFrame:Hide()
/castsequence [@mouseover] reset=6 Thrash(Bear Form),Swipe(Bear Form),Lacerate(Bear Form),Lacerate(Bear Form)
/cast [@mouseover,nomodifier:shift] Maul(Bear Form)
/script UIErrorsFrame:Clear(); UIErrorsFrame:Show()