I enjoyed most of the game but I think it's pretty sad that I beat the hell out of Final Fantasy Adventure so many years ago in a little over 10 hours while I spent around 25 hours on Sword of Mana and I'm barely halfway through the game, and I'm still only around 2/3 of the way through.
I think what really pisses me off are all of the Quests, though. Dear lord. Maybe if it wasn't for Beyond of the Beyond kicking me in the pair many years ago with its brilliant concept of "we'll tell you what to do in a vague way only once, then it's up to you to figure out what to do!" gameplay I would be able to tolerate it, but far too many years have gone by where developers think that vague hints and grandiose Quests that impede your progress are good ideas.
The lack of multiplayer, though...ouch. Shame. Personally, I'd simply lose it if someone would just port Secret of Mana and Seiken Densetsu 3 over to the DS with multiplayer Wi-Fi options. No other upgrades needed. I'd even pay $35 a pop for them, savings be damned.