By a technical standpoint it was an alpha, and not anywhere close to be a beta (good luck to the devs for the deploy-in-production day without having ever seriously tested a recent build).Every time I see the term Alpha being used I raise my brows because imho what's been released these last couple weeks as a tryout can't realy be called an Alpha but rather a close to release Beta.
Hoping for drastic additions or changes when fully released is wishfull thinking imho, we've passed that station before in the past and came out pretty empty handed im my opinion.
From what I've seen so far Odyssey won't be worth my 40 euros, fortunately it won't be released on console any time soon so I'll have plenty of time to see were this is going.
However you're right that we shouldn't expect anything much different on the gameplay side from the release build.
It'll "just" be a technical improvement (hopefully) and some "minor" addition, with a blind release.