Okay, 80 hours in and I think I've pretty out sussed Disgaea; sure, I could grind for another 8,000 hours but there really isn't much point to that unless I just wanna OHKO everything -- which is kinda dull (why have an attack that can take out 10 billion HP while 10,000 already does the trick?)
What I find most fun about this game is not collecting all the top weapons and unlocking all the exclusive characters (as in TO: LUCT) but just enjoying the totally zany story of Mao the Overlord and Raspberyl the Delinquent Teacher (and all the side quests). There are simply too many classes/characters to unlock in Disgaea and not all of them are that great (bad base stats and special skills). I've unlocked about 20 now and I'm, like, no more please!
Though there are all these side missions to be completed, I'm taking my sweet time doing those. As far as the grinding goes, since I have now unlocked the two major items that are vital to win most of the battles, the major challenge here is more about solving the various puzzles (battle maps). Some completionist gamers would replay the story mode or "cycle", like, a dozen times to unlock different endings but, unlike, TO, I don't see the point of doing that unlike you want to level up all the characters to Lvl 9,999.