For lack of deeper meaning, the monsters we are fighting don't really appear to have anything going on in a one vs one basis.

Start leve, sixteen dinkly little rats appear, each one dies in three swings.
Run out into field, every fight above 'decent challenge' results in a sixteen second race to kill it before it kills you.
Difficulty artificially introduced in the form of swarm tactics (which are fine in moderation) and enormous unprovoked AoE damage.
Healers are relegated to mindlessly bashing their area heals simply because monsters vaporize health bars while any attempt at all to chain skills together falls on its face simply because the current targeted monster dies in eight seconds flat.

I would be absolutely elated if individual enemies had substantially more health, a slight reduction in overall attack power, and a greater variation in available special moves.

You have to punish the players just a little to keep them returning. FFXI was astoundingly unforgiving before the era of flamingos and pretty colored treasure chests, and yet hundreds of thousand of people were more than willing to invest in the struggle.

Make
Monsters
Matter