I think each person has to decide for themselves what they want to do, including trying to organize a new version of Webcore or a new UI for the Rules API if that’s the direction they want to go. Maybe they’ll make it, maybe they won’t but it’s their time and money.
Way back when Adrian first suggested Webcore I was one of several people who didn’t think he’d be able to do it. And obviously I was way wrong on that one, it was brilliant work. 
Since then I’ve learned not to try to guess what other people are going to be able to come up with. This is a very creative community. I’ve been really amazed at what some people have already been able to do with edge drivers. And @taustin ‘s MQTT integration is awesome. Plus I never in 1 million years would’ve thought that @lmullineux would be able to build an edge Driver for harmony that didn’t require a server device.
https://thingsthataresmart.wiki/index.php?title=Quick_Browse_Lists_for_Edge_Drivers
I don’t know what will happen with Webcore other than the fact that there won’t be a free Groovy cloud to run it in.
As you say, it’s going to keep running over on Hubitat and that’s a definite option for a lot of people. People who want to stay with ST May find SharpTools A good choice, or be willing to put in the work to learn the rules API. 
As far as complaining… i’ve been complaining since 2018 when they first broke voice navigation in the app and it’s never been fixed. I try not to be meanspirited about it, and I accept it when anybody else says they love the app. But it’s still painful and I still complain from time to time, particularly about the distance between their mission statements and their product delivery in this particular area. and I still keep a little bit of hope that someday they’ll fix it. 
Anyway, if it makes somebody feel better to vent a little, I don’t mind. Again, as long as they’re not hostile about it. The change is aggravating and infuriating and annoying and all that. And we each have to pick the path forward that works best for our own needs and preferences.
So if you love what’s coming, great. If you hate what’s coming, I understand, and as a community we can do the best we can to help each other figure out what the alternative options are.
We can’t say we weren’t warned: the smartthings terms of service which everyone agrees to when they set up a SmartThings account says the company can change anything at any time without notice. No promises of continued operation. But that doesn’t mean the changes come without pain.
JMO, of course.