Hit chance may be high for some monsters in a zone but low for others (e.g. alphabet giant has higher ML). with such monsters one may need to use combat items/spells/shieldbutt etc.I don't see much logic in displaying this during a fight, where the information comes too late to be really useful.
Btw I had this feature as a thread a while back, Bale said it was useful in fact. I do not see it as clutter, it is at most times essential information, and does much more than the current attack/defence info.