Trash items(as i see them ;D) like this allow a few builds using int an almost immediate free 18... effectively handing them a slew of additional build points to work with... not the end of the world to me, just a little cheesy...
Yeah, but you have to agree its only cheesy if you meta game. If you're going for your first run and have no clue, you won't gimp stats that your build needs, so it's up to you to cheese or not.
My "problem" with this item (which, in the grand scheme of things that are currently wrong with the game, is immensely minor), is not so much that it's cheesy or metagamey. I can easily abstain from making a build around it. I just find that, from a reward design perspective, it's very uneven.
If you have made a smart build at character creation (or are using Gale as Mage), and plan for your wizard to have 20 INT by the end of the game, this circlet is meh. You're level 3 when you find it and by level 4 you have 18 INT on your own. But for your clueless friend whose Mage has 14 INT, it's the best thing in the world. It's very useless or supremely good. And it feels like it's rewarding suboptimal play.
One thing I was happy to discover in the 5E rules, compared to the 2E-based rules of BG1-2, is that you don't need to specialise your Fighter one type of weapon. No longer will your axe specialist be disappointed when you find, yet again, a magical long sword. You are not made to regret your early choices.
I would have preferred the Intelligence-boost to be +1 or +2. It still allows you to roleplay a Dwarf or Half-orc Mage, it makes the item somewhat interesting for every party, it makes the item less obsolete in late game, and it allows you to try out a cool Feat instead of taking Ability Score Increase at both levels 4 and 8.