I think Fighters are in a good place, and I like all the subclasses in general.
I offer the Arcane Archer subclass, a rework of the underwhelming version in Xanathar's.
I feel like the Eldritch Knight is much improved over its 2014 incarnation but is a bit behind the power curve in the middle levels. Thus I offer a slightly buffed version of War Bond and an optional feature swap out at level 10.
I personally enjoy the Slayer class from Pathfinder 1e, and miss such an option in D&D. There are of course ways to approximate the concept via Assassin Rogues, and so forth. However, I offer the Eliminator subclass for Fighters as another option.
Side note: yes I know that technically Slayers are supposedly a hybrid of Ranger and Rogue, but they lack spells so Fighter seems a better fit for them in 5e to me.
I offer the Spellblade as a variant of the Eldritch Knight that uses spellbook style casting and focuses on storing spells into Melee weapons.