Benjamin Olson
Hero
I've now heard it argued both that Keen Mind is "bad" because it's useless and "bad" because it's overpowered or gamebreaking. My conclusion would be that it is a feat that requires the right player and campaign. Season 2 of Critical Role has a Wizard who is basically built around this feat at least as far as the player was concerned.
Weapon master seems like an option made only for tables that don't allow multiclassing but do allow feats. But the thing is that playing a straight class in 5e you basically are rarely gatekept by lack of weapon proficiency from any weapon you should really be using long term. There are, however, a few exceptions that would benefit from the feat:
Rogues: Would benefit from whips, but more importantly would benefit from Longbows and Heavy Crossbows. Not really worth even a half feat to bump damage die up by one, but if a cool magic Longbow or such shows up that's a different matter.
Tasha's rules Monks: Tasha's optional "Dedicated Weapon" rule lets them turn any non-heavy and non-special weapon into a monk weapon, but they have to be proficient in it. Absent a magic weapon this is not much of a boost mechanically, but magic weapons happen. Also if you just want to have a non-Kensai pure monk with X martial weapon this is how you do it.
Bladesingers: Have wizard weapon proficiencies +1 one handed melee choice. Just being able to unlock a variety of one handed weapons might be worth the feat, but it also lets them get the handcrossbow which works with bladesong and works beautifully with the Tasha's attack and cantrip extra attack.
Sword Bard: The combat flourishes work with any weapon attack but they only get Bard/Rogue weapon proficiencies + Scimitars. Naturally there are lots of other weapons they might enjoy. A greatsword would even work as a bardic focus for them.
But my nominee for a character idea "built around" the Weapon Master feat is "any straight Forge Cleric build". Basically Forge Clerics get heavy armor proficiency, and boons for wearing it, so they are set up to be a strength build, and thematically they are built around crafting weapons and armor, but then they only get proficiency in simple weapons. From an RP standpoint alone I feel like these guys are born to rock mauls or warhammers, or else use their own very finely wrought blades. They should have martial weapons proficiency, and if you can't bring yourself to multiclass one, this feat is the next best thing.
Weapon master seems like an option made only for tables that don't allow multiclassing but do allow feats. But the thing is that playing a straight class in 5e you basically are rarely gatekept by lack of weapon proficiency from any weapon you should really be using long term. There are, however, a few exceptions that would benefit from the feat:
Rogues: Would benefit from whips, but more importantly would benefit from Longbows and Heavy Crossbows. Not really worth even a half feat to bump damage die up by one, but if a cool magic Longbow or such shows up that's a different matter.
Tasha's rules Monks: Tasha's optional "Dedicated Weapon" rule lets them turn any non-heavy and non-special weapon into a monk weapon, but they have to be proficient in it. Absent a magic weapon this is not much of a boost mechanically, but magic weapons happen. Also if you just want to have a non-Kensai pure monk with X martial weapon this is how you do it.
Bladesingers: Have wizard weapon proficiencies +1 one handed melee choice. Just being able to unlock a variety of one handed weapons might be worth the feat, but it also lets them get the handcrossbow which works with bladesong and works beautifully with the Tasha's attack and cantrip extra attack.
Sword Bard: The combat flourishes work with any weapon attack but they only get Bard/Rogue weapon proficiencies + Scimitars. Naturally there are lots of other weapons they might enjoy. A greatsword would even work as a bardic focus for them.
But my nominee for a character idea "built around" the Weapon Master feat is "any straight Forge Cleric build". Basically Forge Clerics get heavy armor proficiency, and boons for wearing it, so they are set up to be a strength build, and thematically they are built around crafting weapons and armor, but then they only get proficiency in simple weapons. From an RP standpoint alone I feel like these guys are born to rock mauls or warhammers, or else use their own very finely wrought blades. They should have martial weapons proficiency, and if you can't bring yourself to multiclass one, this feat is the next best thing.