I both am super excited about 5.5e as planned, but also would've been ok with them doing a full 6e revision.
For me there isn't any criteria where I would be asking for a full new edition - it's more like I'd be fine with it now but they damn well better not eff it up, and they better have good ideas for how to make the new 6e revision be an actual improvement over 5e and not just change for the sake of change. From that perspective it definitely seems safer to follow their current path, doing minor tweaks to fix things that are obviously busted, while leaving the existing systems mostly intact.
I would expect that 6e version only happens when (if?) players start flocking to other games in droves and DnD playerbase dwindles. That's the only way the risk could become worth the reward