Becoming the Monster

[Fizban]

Not sure what you mean by "make a Raistlin", but at high levels the loss of Con would be pretty painful in any game I've played in. By level 14 there are plenty of sources of "inflated ability scores". Do you play in a game where they've been houseruled away or something?

Raistlin is a party wizard from the Dragonlance books (in the party of the original three, also appearing in spinoffs and with a trilogy centered around a plot of his), a series of novels based on a DnD campaign. IIRC, it was originally played with pre-constructed characters, and in 2e to boot, though there are 3.x versions available. Aside from being a bastard, his big character trait is that he was "cursed" with frailty as part of his test, an explanation for his oh so unoptimized 8 Con.

At 15th a low (8) Con character should most likely have a +4 item, sure, but +6 is still not guaranteed. With +4, their total modifier is +1, which at 15th level is worth 15 hit points. Finishing Green Star Adept removes that +1 and replaces it with a flat +20 hit points: a net increase which cannot be removed, letting you sell or give away your Con item. If you had a +6 Con item, you lose 10 hit points- and gain either 18,000 or 36,000 worth of items. I can play the "there's plenty of bonuses" game too, because I'm pretty sure there's a published item that will give you +10 hp for less than those costs. Heck, for 18,000 you could buy five Amulets of Tears to cycle, worth up to 120-180hp per day and some change left over. Even if you can't use a Wish for base hp, or just make an incredibly simple homebrew item, or make an incredibly simple change to the class, or just not take the 10th level if you don't want to give up your Con, as already stated.

A review of previous threads about ability scores should suffice to explain our differing expectations are.