For sure Dorico's expression map engine is totally superior to Cubase in several ways. Steinberg really hasn't paid any attention to developing expression map feature in Cubase for quite some time, while the Dorico team is much more engaged and this is really important part of Dorico. I hope that their changes will make it back over to Cubase someday too...
I'm still no the fence about whether to use Dorico for mockup purposes, I have a lot more to learn about it. The general crux of the matter is that with Cubase (or any DAW)...you put whatever midi events you want on tracks, in any form you want to get exactly the performance you want. The midi comes first, and is exactly what you want...and if you choose to render a score from that, Cubase will attempt to make the score look reasonable regardless of how notes are nudged around, etc... with some results better then others.
Whereas with Dorico the score comes first, and then Dorico makes guesses or the user manually and tweak the underlying midi to sound how you want, but I think probably somewhat more limited then is the case with Cubase where you make the midi be exactly what you want, vs in Dorico you start with the score and try to massage Dorico into performing that score how you want...with rules..which might work great in some cases and might not in others.
Two completely different approaches to handling midi tracks...and its not clear to me yet whether Dorico is going to be flexible enough to manage any task that needs absolute midi control after starting out as score first.
I love the idea of composing on staves though......and for sure Dorico's expression maps are leaps better then cubase, for the time being...better then all other DAW's too!