Dear Dorico team,
In some scores containing many different compound time signatures, it might come in handy to show the beat grouping above the time signature indication (see picture). As far as I know, this is not yet possible to do in Dorico natively, although it is recommended in Elaine Gould’s Behind Bars (pages 178-179). I would therefore suggest implementing this as a part of the time signature appearence options (or wherever you see most adequate).
All the best!
isn’t this typically done with a dotted bar-line going between the 2nd and 3rd eight notes ? (which I think dorico can do).
I don’t think I’ve ever seen the (2+3) before.
It can indeed be done that way in Dorico, but since Gould recommends this way I think it should be possible.
This seems a logical use of System Text.
If you really need this sort of thing it ought to be linked to the time signatures though.
Otherwise, some poor performer is going to wonder why a bar of 3/4 time is marked “2+3” 
Don’t you know that system text is just a synonym for workaround in the wonderful world of Dorico?
Sure, but for needs that affect only a small number of users, workarounds are a way for those users to write what they want while developers concentrate on more general needs. As mentioned above, there are other ways to show what the OP wanted to show, not to mention the
notation.
Of course there are other ways to show it.
Just to be perverse, I’m working on a project where the composer did it the other way round - the individual staves show two bars of 5/4 and 4/4 (with a dotted bar line between them), and there is a large time signature of 9/4 in the system staff positions.
That’s even harder to fake with Dorico - but I’m not going to bother trying at this stage!
Actually, Gould advices against that particular notation when there are a lot of alternate time signatures of the same length (page 179).
I don’t use it either, but it is available.
I do use the (2 + 3) notation often - but I agree with Derrek that this is best accomplished with system text. Dorico already has tons of options and checkboxes. Anything that can keep the interface as clean as possible is a good idea, I think.
I usually write with an eighth-note pulse, which means the beaming pretty much conveys what I am up to; but I realize that for those engraving others’ music, this is not an option.
Well, technically you are right; it is best accomplished with system text because we have no other sensible choice at the moment. 
Honestly, I switched to Dorico in order to avoid any copy-from-glyph-table,-paste-into-text-object,-realize-the-different-font-sizes-are-way-off,-make-correction-by-painstakingly-selecting-each-individual-glyph-and-carefully-clicking-the-small-adjustment-arrows,-realize-I-changed-my-mind,-redo-most-of-my-progress-over-and-over kind of crêpe. It is way more elegant, intuitive and Doricoesque to just do something like selecting the time signature, go into the properties panel, change an appearance option and then be done so you can go on with the rest of the project. And about the cluttering, if I know my Dorico right, it would make sure that any irrelevant options are hidden until proven otherwise (they do not show the option for flared ends of hairpins if your continuation type is cresc…, right?).
