I think 30F fails not necessarily because the grind is so long (although that could certainly be a part of it), but rather that the grind is so boring.
1. Press M
2. Move a square
3. Fight
4. Repeat until you feel uncomfortable
Do that a billion times.
I'd much rather see something that could be construed as a "run". Imagine the floor was a large labyrinth with a bunch of switches and a boss at the end that respawned every time you entered. If you got to the boss and defeated him, you'd get a large payload of XP and skill points based on how many switches you turned on that run. The idea would be that you'd, over time, get stronger and thus able to take more diversions to turn on switches and still successfully kill the boss.
While the idea is the same (grind grind grind), I think I'd have a lot more fun doing that than the aforementioned step-battle-step-battle routine.
Edit: Yesssssssssssssssssssssssssssssssss

Marisa with the Master Spark victory.
Tenshi, Rumia, Shikieiki, Kaguya handled 95% of the battle. Once he got a lucky shot onto Kaguya, it became a game of "rotate the benchwarmers".
I guess the good thing about Winny having so many moves is that there's a good chance he won't use any of the scary ones.
For those just tuning in, this was a "random party" run, where I wrote a program to give me a randomly assorted team of 12 out of the 40 available. The team I got was:
Marisa
Alice
Rumia
Aya
Tenshi
Flandre
Kaguya
Yuyuko
Maribel
Utsuho
Mystia
Shikieiki
Clocked in at 83:25:26.
Might as well share some thoughts on the characters I got to know very well.
The GreatsTenshi: Well, I didn't have much choice for tanks as it is, but that doesn't mean Tenshi didn't wall it up anyway. She was one of the last to overcome her SP limitations, but she's not a sweeper by any means so it generally only mattered in the really long battles. Alternated DEF and MND level up bonuses.
Mystia: Fantastic non-elemental sweeping, pretty good non-elemental boss plinking, my best poison and paralysis on a multi-target move, and my only form of status ailment healing--wonderful. All ATK bonus levels. Probably could've gone for a tank build, since I didn't have a really solid slot 2 for the entire game, but I regret nothing.
Shikieiki: Really only started to come into play near the end of the main game, but truly ridiculous from that point on. Once you've got the SP to judge, you freaking judge. Her + Kaguya is one of the strongest things I've seen in LoT1. A +80% ATK Shikieiki judging you every 5000 delay is ridiculous. She ended the game with 3 Gurthangs, which meant she had terrible PAR resistance. Oh wait, Buddha doesn't care! All ATK bonus levels, of course. She was doing 4 million damage a pop vs Winny. Oh, and if the enemy is weak to debuffs, she brings it home.
Kaguya: If Buddha's Stone Bowl wasn't ridiculous enough, Kaguya sweeps like a boss with Hourai Barrage. Her other 3 skills didn't see much play (and Dragon's Necklace, uh, none?), but that doesn't really matter. Pure MAG bonus levels. If I did it again, I'd probably go pure MND tank, since Buddha doesn't care, but Hourai Barrage is still incredibly useful, so I dunno.
The GoodsYuyuko: Saigyouji Flawless Nirvana can compete with Hourai Barrage in terms of damage if the enemy doesn't have super MND, and even against enemies that shut her out, her ATB damage is unmitigatable. It's too bad she's so slow. Pure MAG bonus levels.
Flandre: Do I even really need to say it? Pure ATK bonus levels. Ended the game with 3 Rhododendron Dresses.
Marisa: Starts the game as an excellent sweeper, ends the game as an excellent nuker. Ended the game with 3 Eggs, giving her 92% regen. Since you only need 1160 to optimize Master Spark, you can definitely shoots out tons of damage in a single battle this way. Pure MAG bonus levels.
Rumia: My only healing, and her and Mystia made sure no one on my team was ever debuffed. She was instrumental to many boss fights.
Aya: I'd always passed up Aya for Chen in my other runs, and, after this run, I would probably do the same. However, just because Chen is god tier doesn't mean Aya doesn't have her uses. While WND is generally a shitty element, Sarutahiko's Guidance was incredibly useful for buffing Rumia for more heals, and--you guessed it--Kaguya's speed so she could give Shikieiki more turns. It's roundabout, but damn it it works! She also had good uses as a sweeper early to mid game. Pure ATK bonus levels. Would probably do SPD if I had her again.
The Awww...sUtsuho: Poor SP growth, which is bad because you need to cast her spells a bunch of times to get her doing damage
comparable to everyone else. Debuffs herself (although that was not much of an issue with Rumia and Mystia). Awful ailment resistances, too. While her MAG stat is high, her level rate is low so she breaks even mostly. But her ability equations are really lackluster, which accounts for the low damage even at +80% MAG. Pure MAG bonus levels.
Alice: I have no idea why you'd ever have Alice in your team past Rinny. She gets points for sweeping effectively in the early game, but she does very little past that. Her boss nuke doesn't hit that hard, and has surprisingly bad delay. Her debuffs are
okay, but have little utility once Shikieiki gets going. Pure MAG bonus levels.
Maribel: Um. What? Could sometimes sit in slot 2. Pure MAG bonus levels.
I want to finish out my inventory before I call it quits, which means I need the 3 final boss drops and Yukari's drop. Shouldn't take tooooooooooooooooo long...I hope?