While I think the show was phenomenal I think S5 & S6 were the two weakest seasons (while still being very solid). I think there was a lot more fun to be had with certain characters. Far too little time was spent with Jessie Eden (the character interactions between her and Tommy were so fucking well done), Ada (a critical part of what made family interactions so great), Pol (she should have had the second most lines imo), and Michael (a great foil for Tommy and a really fun source of drama both as an ally and as an enemy). Also, Arthur was too much of a caricature of himself in S5, though they largely fixed that this season and did a FUCKING FANTASTIC job with him in the final episode, holy fuck.
Really speaking S5 and S6 could have benefited from two more episodes apiece that would have allowed them to take a slower pace with every scene. Every single modern great show seems to have this problem where they decide they're going to deny their golden goose their swan song (how do you like that mixed metaphor). Why they insist on this after the fiasco of GoT is beyond me. Thankfully the writing and acting is still top class here by and large so whatever issues there were were outshone by all that was good about it.