We don’t necessarily have the same specific needs, but those of us who share your pain when it comes to Dorico as a composer and mockup tool are glad you have added your online “voice.”
Those who don’t see the need (for whatever reason) often respond, “Why not just use Cubase and let Dorico be an engraving tool?” My answer? Because some people prefer to experiment, compose and audition using notation. To audition you need adequate playback using third party VST’s (for me it’s VSL) matched to articulations with reasonable effort. You need the ability to flexibly select material to audition. You need to be able to capture complexities with CC values with reasonable effort. Sure, final mockups can be done in Cubase, but prior to that you need an adequate provisional mockup. I agree with you that the Halion stuff just gets in the way.
Just because some people prefer the engraving aspects of Dorico almost exclusively doesn’t mean everyone must think the same way. As you say, Notion has been the best platform for this type of work, but it is needlessly tedious when setting up and using third party VST’s. Overture 5 apparently has some promise, but it’s essentially a one-man operation so far as I know.
I get that some people, a lot of people, have no need at all for such features. Just like I have no need at all for sophisticated engraving. All I ask for in that department is reasonable capabilities implemented with quality. That has already been accomplished before any paid update. I wonder why so many engraving users often don’t seem to get that others have different priorities, and that’s okay. It’s as if, “Duh! Dorico is a notation program! It’s all about the engraving!” Ah, but Dorico was promoted as much more than that. On that basis, I bought it to supplant Notion. Like you Dorico is a software brick for me at the moment. I have hopes that it will not remain so for too long, but I admit my hopes are beginning to fade off into a years-long future of mandatory paid updates (since updates will be cumulative) with no assurance at all when my brick will turn into a tool.
Your voice is not a lone one.