You're dismissing Action Surge and Second Wind as if they didn't exist, while they are two very impactful features in my experience, especially since you can short rest after every major encounter.
I agree that the subclasses feel underwhelming, but I still see reasons to pick a Fighter over a Ranger: you don't lose that much damage potential, but you get a sturdier character in return. It's harder to justify the Fighter over the Paladin though, that's true. I played through the game with Fighter/Paladin/Cleric/Wizard and Ranger/Paladin/Cleric/Wizard, and I felt the first group was better (same thing switching the Paladin for a Rogue).
Even if no Fighter archetype is interesting enough to me, the +2 AC of the Mountaineer makes for the sturdiest character in the game right now. In my Fighter/Paladin/Cleric/Wizard playthrough the Fighter got hit three times in the entire game. There are very few encounters where you can't position yourself with a wall on your side. Though I admit it's sad that Cleric, Paladin, and Wizard got completely broken archetypes while the Fighter got a +2 to AC.
The biggest problem right now are feats. There are no useful ones apart from Sylvan Archer (and even that is just a nerfed 5E PnP feat), so 1/3 of the benefits of playing a Fighter (being able to pick feats without gimping your abilities) has no use right now. I THINK they will add more later, since everything else regarding character creation feels much more polished.