I simply don't buy the notion that the "ceiling" for the Brewers is to meekly bow out of the playoffs every year because they can't afford to field a roster full of bloated veteran contracts over $200M. And there's also more to it than playoff randomness - the Brewers have built rosters prioritizing defensive versatility and run prevention, and how those rosters are managed over the course of a regular season doesn't appear to line up well with playoff success. That falls on both a team's front office and manager - particularly with CC and how he did carry some sway with how the 40 man rosters have been put together and managed over the years.
From an onfield perspective, I'm ok with CC no longer managing the Brewers even if it means the Brewers take a step back this season - I think it was time for both parties to move on in order for the Brewers to take a different organizational approach to try and win a title instead of treading water. I also don't expect the Brewers to lose 20 fewer games just because CC isn't in the dugout anymore - W/L record depends more on the quality of the roster they'll be working with.
And, I won't hold it against CC personally to go manage the team that threw an insane contract at him, even if it's the Cubs. However, I'll also have no problem holding him unnecessarily more accountable for them failing to win WS championships because they're paying him like he can find ways to consistently win in October when his onfield playoff results are anything but. As a big market club, the Cubs don't need the best manager in the history of baseball based on what they're paying him to make the playoffs consistently. If there aren't WS parades on the north side in the next couple of seasons, CC should get more heat than he deserves.
The Brewers have built their recent window off dominant bullpens with plenty of depth to navigate through 162 games - CC gets credit for adept bullpen management, but he's also been given a ton of bullpen talent to work with. One way to really handcuff that organizational strategy is to be poor at developing pitching, not identifying journeyman relievers capable of big years with small mechanical/pitch selection tweaks, and instead throwing a pile of free agent dollars and prospect capital to build a better MLB bullpen. If you get that typical reliever volatility with high-priced relievers or a key injury, you then get stuck with them and cheaper internal options with talent still aren't on your 40 man. Essentially, this likely describes what the Cubs are about to try and do over this offseason.