Non-combat and non-stealth feats that did not grant a +1 to a specific ability I would look at adding it to. With ASI such a nice option, the only feats that seem to be able to compete at low-to-mid levels are combat-oriented feats, but I think the non-combat feats like Actor add a lot to personalizing your character. I'd rather not see a character played for 16 levels before it "suddenly" comes out he's a skilled actor. (Side note, Actor does give +1 Chr, so it's nto one I'm suggesting changing - it just happens to be one of my favorites.)
Other changes:
Heavy Armor Master: Change the damage reduction to be equal to your Proficiency bonus. This tones it down slightly at low levels (only +2), but scales it some so you don't regret taking it at higher levels. (Goes from 3 in original to 2-6 now.)
Linguist: Add in able to pick up new languages in reduced time with the normal downtime rules.
Lucky: I'd change the defensive aspect to "when hit". You ARE lucky after all, doing it on a roll that could miss is a bit pointless. And if your DM doesn't tell the original die you could turn a miss into a hit.
Mounted Combat: Scaling on this is really DM-dependant if the DM allows the players to find level-appropriate mounts. I'd like to adjust it to put a floor on your mount's HPs, AC and saves so you could find better but always have something at least usable, but I'm not sure how.
Polearm Master: The opposite end attack does not have Reach or Heavy keywords even if the weapon does. This one of the top three combat feats, and having an easy bonus attack with reach, magic of the weapon, Str to damage automatically, and could qualify for Great Weapon Master, is a bit much for a bonus attack.
Ritual Caster: Add into the first sentence of the last paragraph: "If you HAVE A SPELL PREPARED or come across a spell in written form, ...". This allows you to scribe spells you know into your ritual book and spend a feat to effectively get the Wizard's ability to cast rituals without preparing them that day.
Savage Attacker: Change it against the Sage Advice clarification and allow you to reroll all the dice associated with the attack. For a feat, it does remarkably little as written. A longsword (d8) it changes the average from 4.5 to 5.8125. So as a feat it adds about 1.3 hps of damage per round. Negligible and nigh worthless.
Skilled: In addition to granting +1 to the appropriate ability (see above), I'd also reduce downtime needs for learning future tools.
Tavern Brawler: Add the Finesse keyword to your unarmed strikes. So you can play an agile brawler as well.
Tough: Your Hit Dice no longer keep up with your HPs, so I'd add 2 to each of them to balance it.
Weapon Master: I'd rename it to something like "Martial Training", simply because Weapon Master sounds like you should be badarse with them, but if you didn't even have proficiency before you're probably just meh at best.
