OK. So, I'm not particularly happy with the instrument proficiency thing. Who's going to waste a Feat on gaining the ability to play an instrument?
In 5e, many backgrounds and such provide instrument proficiencies. For example, my Ranger Ryth-Shan is an Outlander and has Lute proficiency at Level 1. He has 0 Performance skill, but he can play an instrument.
I'd like more ability to have other characters play instruments. Not just the bard or if I waste my Level 4 proficiency for it just so I can have my characters all playing like they're in a band. Either make it so that if someone picks the Performance skill they automatically gain a proficiency in 1 instrument, or make it so that certain backgrounds, like Entertainer especially but also Outlander (there really aren't that many backgrounds), provides instrument proficiency.
Don't worry, just because they are proficient in an instrument, it doesn't negate the Bard's class. The Bard is still WAY better with instruments because they cast spells with them and get way more perks and buffs with instruments. Those with Entertainer or Outlander backgrounds can just play them. Doesn't mean they're good at them, and they certainly don't cast spells with them.
Either way, it'd be nice to have.
