You already could do this in TTYD for all realistic purposes.
I put my first level in FP, then every single level after that into BP except one level each in HP/FP around the start of chapter 4, and one more for each at the start of chapter 7.
I finished the Pit of 100 Trials with 20/20/84 as my stats (did not grind levels at any point in the game, but beat it post-game) and found it absurdly easy--only took damage on Mario two times going down, and one was when I tattled an Amazee Dayzee since I didn't see any in chapter 4 while I still had Goombella. Used nothing but Point Swaps for infinite FP/easy peril on partners and one Life Shroom for that Amazee. --- "That is why war is so tragic. To win means to make victims of your opponents and give birth to hatred." - Kratos Aurion, Tales of Symphonia
Yeah, it was confusing for me because I had never played PM64, only PMTTYD, where that system is actually put into place more or less. I mean, you could be a level 30 with 10 HP 5 FP and 99 BP or whatever. --- Don't eat soap! Brush your teeth instead!
Ok, have you even played PM64? If so(which I doubt) your max level is 27.
MAX LEVEL IS 27.
Ok? Got it?
And if you get to 27 your HP and FP is 50, and BP is 30.
I don't like this, I would rather raise my BP all the way until I reach character level 27. That'll be 81 BP.
Understand? It's not rocket science, really.
Wait, you can't level up past twenty-seven? And your stats will all be maxed by then?
Weird. But you can already do that in Paper Mario 2. It's not rocket science, but it helps to word it better. --- This just in: Scientist sticks hand in fire, burns, and declares fire "hot". Film at 11. -Nash_Clovis