Tavern Brawler is incredible on just about any Str based character, if they can fit it in. Tons of great Strength based feats of course, but one should not underestimate how much damage and flexibility is gained for a Barb by carrying a bag of axes and a ring of hurling in conjunction with Tavern Brawler. +5 (or more) to hit *and* damage is just insane. It doesn't need to define your build, though for many after seeing how strong it is, it might take over anyway. Let's assume "only" 20 Str and compare for a variety of to hit percentages, compared to what is known and widely acknowledged to be one of the strongest feats in the game, Great Weapon Master:
Tavern Brawler throwing a Handaxe (1d6+5, now 1d6+10), hit percentage increases by 25% thanks to the feat
Normal Hit Percentage 10% (goes to 35%)- .85 expected damage without the feat to 4.72 with the feat
20% - 1.7 to 7.42
40% - 3.4 to 8.77
60% - 5.1 to 11.47
80% - 6.8 to 12.82
90% - 7.65 to 12.82
Great Weapon Master going "all in" with a 2d6 weapon (2d6+5, now 2d6+15), hit percentage drops by 25% thanks to the feat
10% - 1.2 to 1.1
20% - 2.4 to 1.1
40% - 4.8 to 3.3
60% - 7.2 to 7.7
80% - 9.6 to 12.1
90% - 10.8 to 14.3
As we can see below 60% base hit percentage it's not worth using, that actually rises as the amount of additional damage sources increases. But Tavern Brawler is not only always a boon, it's such a huge boon that in most cases they're doing more damage with it. This is of course why it's so critical for a GWM user to have Advantage from somewhere, to ensure their initial hit chance is high enough to be worth it. If instead you were say throwing a pike of returning, with a ring of hurling on, it would be even better. Of course you can't for example Smite off a throw, but even still, it can be very nice to have that option in your pocket as it were.
I also personally like Moderately Armored on pure Rogue, it's better than just an ASI since no stat beyond Dex matters that much, and it means you don't have to dip. Given that I think more than a level off is too much (Reliable Expertise is just too good to miss), it's really a matter of a 1 level dip in Ranger or the feat, Ranger would give Heavy Armor Proficiency instead and some goodies, but +1 Dex modifier (and keeping it "pure" Rogue) has merits of its own. If I liked Fighters better I'd definitely try Heavy Armor Master, if you have Blade Ward up consistently (as you may thanks to healers having a certain item) then that could really make up for the lack of HP vs Barbarians and let them serve as more effective tanks.
