I guess what I like about C:ME comes down to balance...Much like TF2 the weakest class (archer) can hold his own in melee against a Knight if he times his attacks well, blocks well and stays nimble. A Knight can add a distance weapon but loses his shield. Each advantage has a trade off. Is this historically accurate? NO. Is it fun to play? YES.
The balance makes it fun no matter what class you play...I can't talk from experience but my friend said WOTR seems to descend into all "heavy" classes due to them being OP.