Being +2 Int instead of a fixed 17 would make the Headband of Intellect actually useful for a Wizard who is an Intelligence class
It would make it TOO useful, which is precisely the problem: it’s supposed to be an “entry level” magic item that looks absolutely amazing at first but turns so-so in the long run. Making it a flat + would make it amazing no matter what.
Still, +2 is far less than +9 when you go from 8 to 17. Dumping Int leaves you a lot of points to put into Str/Dex/Con which is the main source of OP here.
Could also be +1 Int because that one is damaged. Or +1 with a bonus spell slot or an Arcane Recovery type ability to make it relevant even if the +1 Int does nothing.
