If only one subclass is valid in two pillars of the game the class has a problem.
For the love of Orcus THERE IS NO PROBLEM.
It's only a 'problem' to a small core of whiners that raise the same points over and over and over again, in this thread (and threads like it) that they spawn every week, and have done for years now.
Overwhelmingly (in survey after survey) Fighter is actually the most
popular class. It dominates the combat pillar (likely why it's so popular) and I've already demonstrated (repeatedly) there is nothing stopping from creating a Fighter that is top tier in other pillars as well.
The Fighter is also the most heavily nerfed (by house rules) and most frequently complained about as being OP class in the game as well.
Examples include:
DM:
I dont care about HP, my game has insta death for (falling, lava, assassinations etc).
Effect: Deprive the Fighter of the benefit of his class feature (d10 HD) and nix his Second wind while you're at it. Those HP are expressly there to give him the Plot armor to survive such things, and they're a class feature. Ruling they dont matter in some cases (when the rules clearly and unambiguously say otherwise) punishes the class with the higher HP the most.
DM We use fumbles in my game!
Effect: punishes the Fighter for no other reason other than 'advancing in level' and does so more than any other class with Monks around the same area, seeing as Fighters (and Monks) make more attack rolls than any other class in the game (especially casters, who can go 20 levels without ever making an attack roll).
DM:
We use flanking!
Effect: Punishes martials, because they now get advantage on them, most of the time, by most monsters, and who is up the front getting flanked in the first place and doing his job? The Fighter.
DM:
GWM/ SS are waaaay broken so i made the following changes...
Effect: Hurts the fighter the most, because they make the best use of those feats, more than any other class.
DM:
Oh we dont use the 6-8 encounter/ 2-3 short rest Adventuring day. We have one 'super deadly' combat encounter per long rest, maybe 2 at most!
Effect: Hurts the fighter the most, along with any other short rest dependent class like the Warlock.
DM:
In my games we impose a level of exhaustion on anyone who drops to zero HP...
Effect: Impacts people getting hit the most (Fighters and other martials), and who actually give a toss about most of what Exhaustion does (unlike casters, who don't care about half movement, or disadvantage on skills and attack rolls anywhere near as much as a Fighter would).
I could go on an on and on an on.
You people complaining about Fighters (and indeed all Martials) are a broken record. I absolutely assure you there are other factors contributing to Fighters 'performance issues' at your tables, and I bet you it isnt the fault of the Fighter class itself.