If there was no change other than adding the attack(s) after trample, SCs/thugs would be VERY nasty. Enc 0 is ALREADY a huge bonus, and we don't want to make undead thugs summons even MORE prevalent than they already are. Well, what I think they are.
I don't actually play that many long MP games.
However, if trample items (Stymphalian Wings and Boots of Behemoth AFAIK) added -4 att and -4 def, and most trampling units would have lower att/def rating than other similarly priced units (as is the case with Minotaurs already), I don't think it'd cause too many problems... Still, to answer the original question:
TRAMLING WOULD RULE! 