The reason you stick to your class is to benefit from being overleveled the whole game starting with the level where I didn’t dip.
Yeah unlocking that keystone is fun when you do but unlocking the other 18 levels on time is the value.
I'm actually not a big supporter of armorless combat. And I generally dislike the various 1 level Vivisectionist dips.
But there are builds/classes where dipping that 1 level in monk early does provide huge value.
A Sword Saint being one. As well as various Dex-based melees, particularly other maguses, who suffer spell failure in armor until later levels.
In Kingmaker if Lawful Good, that 1 monk level offers like +12-14 AC (actually +16-18, because it also offers "free" Crane Style, which makes Defensive Fighting worth using).
That's a rather huge swing.
In Wrath I dip Sohei all the time - to have a good building tempo and get fast Spirited Charge. Sometimes also to get extra attacks from Weapon Training Flurry.
Also I regularly take 3 Gendarme Order of the Cockatrice levels - for 3 feats (with Dazzling Display from Order in time for Shatter Defenses on 7 or 9), +2 AB vs Shaken enemies and +2 AB on Charge.
I'd need the breakdown on that math. If you're already WIS/CHR-based it can be sort of worth it IF you have to tank early and IF you want to play Unfair the whole game but those are big ifs.
I think you and
Daidre do more solo-style (though there you do still miss out on the capstone which is the only thing people usually think about, and it does matter more if you're turbo-leveling) which forces you to have to tank more in general since fights will last longer and gives you less options for letting a companion (or their pet) do the tanking before your own AC fully develops.
And yeah I'm not big on exploiting the Wing bug but wouldn't bother in most cases even if I were. AC just isn't a critical stat since you get enough already to survive almost anything and those things have other ways to attack them.
I mentioned Lawful Good because of Protector's Robes: 5 AC + up to +9 Wis/Cha mod (+3 start, +4 headband, +1 Elixir, +1 Ring of Circumstances), then you also get "free" Crane Style to enable +4 AC when Fighting Defensively with 3 Mobility (I normally skipped Dodge and Wing).
Its a bit less if you don't have enough Dex to match a Fullplate - but with Bracers +8, you need +8 Dex mod to match a +5 mithrall plate, which isn't a lot. Or 14 Dex + Elixir + Belt.
I don't actually play solo. I like the party buffs/debuffs (like Dazzling/Demoralize+Shatter, Haste, Heroisms, Freebooter's Bond+Bane, Evil Eye, Metal Curse, Hampering Hex, Protective, etc.) and the occassional CC too much for that. Also I'm not too keen on some building rigors that'd force. And I don't have the patience to play on Unfair much.
I'll admit I do like my main char to be the star of the show, though