He will be god tier ninja for 9tails for earth and water for sure, with high possibility for other classes too. As for other classes, even though barrier doesnt buff them, you still get 50% dmg boost which is multiplicative with total damage, not base damage.

Assuming you run elemental enhancement, asuma wb and iruka, you deal total of 100(base)+40(elemental)+30(iruka)+30(asuma)=200%tai/nin dmg. Barrier makes it 240%, but as that buff scales off of base dmg, real difference is 20% more dmg [(240/200)*100%], while yamato works like unparalelled, which increases your total damage by 50%. So if you only swap barrier ninjas for yamato, you deal 200%*1.5=300% (360% in case of water/earth because they benefit from barrier) instead. He's going to be best barrier ninja for every main, even better than hashirama. At this point you can safely auto (pompt barrier on move1) if you manage chakra correctly, so main uses mysteries while available.