Definitely agree with that, I don't think I can find any other shows that have as solid an ending as The Shield. Maybe Breaking Bad, but I felt The Shield had more weight to it.
As for the actual ending, I think Vic found a way to turn his ICE job into a successful fed career. He's crafty enough to worm his way out of sticky situations and I think he'll have allies within the department to help him.
He wouldn't. Vic's fate at the end amounts to two options:
1. He says "fuck it" and throws his life and second chance away to free Ronnie from the prison transport van taking him to jail, killing multiple cops in a potentially futile last ditch gesture to salvage the one fuck up he could fix (freeing Ronnie) and either dying doing it or basically getting killed by Ronnie first chance he can, or both men basically fleeing to Mexico with just the clothing on their backs and a giant bullseye on their back from the authorities to the Mexican cartels wanting them dead
2. Vic suffers in silence at ICE while trying to find his kids or at least, get Dani to give him visitation with his son and when that fails, vanishing in thin air when his three year contract is up since his life is ruined and his only hope is going some place on the east coast or middle america and getting a boring normal person job.
iirc season 5 was supposed to be split in two parts and it was to be the final season. fx throw a dump truck of money at shawn ryan and we got two full seasons.
story wise, i felt the last two seasons were filler and should have stuck with the original plan. but the last two episode were good. especially, the vic mackey confession to the feds and the claudette interrogation of vic.
fx brought back justified, why not bring back the shield.
Confusing shit.
Season five was going to be a regular season with an option for it being the final season if the show didn't get renewed for season six in a timely fashion. The episode order count got upped THEN the order came, to save money, that they were going to split it into two. And Forest Whittaker, who joined the cast as an attempt to recapture the lightning in the bottle that was Glenn Close's run in season four, started getting major buzz for Last King of Scotland which put a lot of eyes on the show and it's fifth season.
The plan, until they split the episodes for two seasons, was to end season five with Lem's death. There were rumors that they were also going to kill Ronnie too (and reveal Ronnie was Dani's baby's dad for added angst) at the end of season five so season six would be Vic vs Shane. But the split saved Ronnie from dying and they made Vic the baby's dad, combined with the writers deciding that Shane killing Lem needed to be less gruesome and soul crushing (originally Shane kills Lem full-on execution style in a slow, soul crushing scene but they changed it to the grenade death to make it quick and less painful).
Originally Kavanaugh was going to be gone for good after the first block of episodes/season five. But Whittaker had fun working on the show and offered to come back for several episodes in season six to wrap up his characters arc so long as they put them at the front of the season to accommodate his schedule. The second half of the season was plagued by not knowing if the show was renewed or not for season seven and generally speaking, the writers spinning their wheels. And season seven had to be rewritten from scratch when production was delayed due to FX moving the final season to the fall not the spring combined with Walt Goggins not being available for only a handful of days for the final third of the season and the chick from Run Lola Run declining to return for season seven (which might have been for the best, as Vic's daughter was supposed to be heavily involved in the original ending of the series, combined with an episode where we would find out that Ronnie was bisexual and been sent to a conversation therapy facility as a teenager, which would have been the mea culpa to fans for the controversial "pray the gay away" storyline the Julian character had as a condition for Michael Jace to continue in the series).
Also, the reason there is no Shield revival is that the ending went full scorched earth on any sort of continuation unless you completely excise the Strike Team. Also, SWAT basically is Shield but everyone's happy and well adjusted and features alt versions of Ronnie (a regular detective) and Lem (a SWAT officer) in it, as far as being an alternate earth what if scenario for "what if Ronnie and Lem never met Vic and Shane and avoided being corrupted by them and their lives destroyed".