Yes in general, with a big "BUT" coming...Is this sort of thing something you would be interested in? If so, what would you like to see in it?
I'm actually okay with this; even if some stuff is reprinted, having everything in one place is, as you say, convenient.
- The fighter class reprinted for convenience
Not interested. I'm actually not a big fan of subclasses. Rather than "customization" my feel has been they make your character cookie-cutter... your subclass character is exactly the same as every other subclass character. And you probably have abilities in your "ability set" that you don't even want.
- 50 (?ish, maybe not that many) new fighter subclasses
As long as they are mechanically unique, this interests me.
- New equipment, weapons, armor
Tell you what, give me 50-ish new Feats - something EVERY subclass can use - instead of 50 new subclasses, and I'll be happy. A Feat is potentially applicable to EVERY subclass. This is the opposite of subclasses - universal instead of super-niche.
- 20+ new feats
Depends on what these rules are. For example, I'd love to see more advanced combat maneuvers, perhaps tied to weapon classes like axes, spears, etc.
- Optional new rules
Having 40+ years of experience, I don't know that I'll see a lot new here, but I'm not actively against it. There are far more players newer to the hobby for which this will be new ground and I want to see new players get excited, too.
- Role playing advice, seeds, hooks, etc. to make your fighter your own.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.