Should be decoupled from Fighter and tossed into the Feat pool. But what would be we call a Feat designed to boost your Combat abilities? This is the problem with the Fighter as a class. For other classes, role
D&D5e subclasses are very versatile. Even with a party of four you have plenty of options. You can make a Bard All-stars party if you want to. Githyank/MountainDwarf - College of Valor bard (Outlander) - Main tank [OPT: 1 level of Fighter] ...