I haven't upgraded yet, but judging by the Discover Dorico rundown, the new features look very nice.
The divisi feature seems particularly slick and useful, although unfortunately, it does not yet include the reverse option of condensing two players into a single score staff, while keeping separate parts. Until the inclusion of such a feature, you'll need to work around this by creating separate flows or projects for your parts. This is cumbersome, but not much different from the traditional way of extracting parts, which I regrettably still have to use in Finale, because of certain limitations with the dynamic parts feature.
With regard to customisation, one major new improvement, apart from any playback related ones, seems to be the playing technique editor, where you can create, categorise and customise the appearance and placement of playback technique symbols. Since these evidently can be based on either font glyphs, graphics or even composites of the two, the editor seems powerful enough to rival many use cases of Finale's shape designer, while hopefully being a lot easier to work with.
There are also smaller additions to the flexibility of elements such as dynamics, fingerings, text, etc., and although Dorico still seems to be quite far behind Finale in terms of strict flexibility, I'd say it's coming along nicely in that department, while being a major improvement in many others. And I'll add that since there apparently won't be any improvements to Finale's functionality for at least six months, Dorico still has that time to close the flexibility gap further.
BTW, you can read and watch more about the new features of Dorico 2 from the links presented here