Yeah, I guess I'm classed as a long-time 'power user' over there too, also finally sacked it all off and came here for my first c7. Amazing, BTW.
Samsung openly admitted that their servers were getting hammered by people like us who were using custom code, smartapps, webcore etc. Don't think they ever expected that kind of drain. At the end of the day I spend a few quid on a smartthings hub years ago and essentially didn't give them any more money after that. Purchased a load of non-Samsung smart devices, and continued to use their cheap hub to run it all by constantly battering their cloud servers.
Not suprised they pretty much disabled it - but instead of first getting a workable solution in place, they chose to (imo) deliberately ■■■■ up the current (well, classic) system by removing various features, and released an effectively-alpha product in its place. Might be great for seeing the status of one of your Samsung fridges or whatever, but is a big bag of wank for everything else.
Job done. Most of the techie users got sick and left. Hence the new faces here including mine! Not to say I'm particularly great at making anything in the way of software etc, but I do extensively make use of this gear to do cool things around my home (custom zoned central heating, propane powered hot tub, security system and the usual lights etc).
They really screwed up, intentionally. They didn't want us there. The product is currently worthless. Maybe things will change, but why wait. Hubitat is ace. Thoroughly amazed by it.