Grinding on the first one was required, which they seem to have gotten better at in the later games, but the gameplay is still off.  Weapons are so varied in stats that you'll have to waste turns with other characters just to feed weaker characters with kills so they're not severely outclassed.  

The only game that this concept has worked well on, or atleast well enough, was ZHP The Unlosing Ranger vs Dark Death Evil Man.  A rogue like within a Disgaea like world with weapons, armor, and items from Disgaea.  As a TRPG if you don't like the games end game side content with the mass amount of grinding, then it's best to just pick up a different better TRPG.   

really good numbers for a sprite based 60$ game

Anything over 80 is amazing for a JRPG. Tales of Graces had like a 78 and I thought it was amazing.

Still at 81 with 17 reviews. This is likely to be one of those filler games I buy when there's nothing substantial out.

Aren't these games like ridiculously long?

Story wise they tend to be about 40 hours but you have the item world which is endless and other side distractions.

http://howlongtobeat.com/forum.php

Look at the huge difference between the those playing times and you'll see how much extra content there is.

http://howlongtobeat.com/game.php?id=2595

Average Completionist time: 560 hours.....well, ok then that's one game I'd never complete. Lol