I think the HBO Max app itself could have been more impressive; it was essentially just the old HBO Now app with a fresh coat of paint and one new feature added: profiles. Should've had 4K HDR at launch, along with some degree of personalized recommendations, plus live feeds of at least the main HBO linear channel. (It has at least added show-related podcasts since launching.)Sounds like an acknowledgement they screwed up the hbo max rollout
But when most folks talk about a "screw up" of the HBO Max rollout, I think they're mainly referencing the fact that the app isn't on Roku and Fire TV. I doubt that would have turned out any differently with Kilar and his new team in place; Roku and Amazon are just insisting on distribution terms that aren't acceptable to Warner. Hopefully a compromise will eventually be reached but both sides are so far apart that neither would have felt the need to compromise further without first launching without the app on those platforms.
Beyond that, I'd just say that HBO faced a MUCH trickier launch for HBO Max than they would have for a completely new service, given that HBO Max was building on a big service, HBO, that was already being distributed by LOTS of companies, plus the fact that it was designed to replace not one but two pre-existing apps, HBO Go and HBO Now. One of the head guys at Netflix years ago said he bet that Netflix could become HBO before HBO could become Netflix. He was right.