Old Garen was weak outside of bronze-silver elo. Actually not just weak, he was totally useless, most people know what spacing is and that pretty much negated anything Old Garen could do. The Villain mechanic was the worst thing they did to him and it caused him to be incredibly overpowered and then incredibly useless again because he needed to be nerfed.
This Garen is nothing, yea he needs some fine tuning (lower early E damage and his Ult does too much true damage), but other than that he isn't even a problem. He gets countered by a bunch of meta top laners and is super susceptible to ganks, if he can't leave laning phase with a lead he is useless for the rest of the game. Learn spacing, learn how to kite, learn how to play against him, DONT STAND IN HIS E AND TRY TO TRADE WITH HIM. He is simple which makes him strong, but it also makes his counterplay simple and easy. There is a reason why majority of the complaining about Garen is coming from Low Elo players, they don't know how to lane or trade or kite or how to control a wave. Yea he has above 50% winrate in Plat and above, buts its falling pretty consistently and he hard counters certain champions and is fairly new still.