I’m currently engraving a piece where the music is a mix of 4/4 and 2/4 bars, pretty randomly, changing almost every bar.
The composer has put a double time signature at the start, of 4/4 2/4, then uses either bar length within the piece without indicating further. Non standard, but it works fine in practice!
I guess this will require some creativity to realise in Dorico, as it’s not a strict alternating time signature?
It’s easy in Sibelius. No reason to assume it would be any less easy in Dorico.
It’s very easy to do even in Cubase Score… 
We have different definitions of “easy” But this isn’t a Sibelius forum so let’s not debate that.
I raised it because I read that Dorico has good support for alternating time signatures - but this is less rigid than that.
I suppose you could have a completely linear entry method - “enter notes, enter barline, enter more notes…” But “enter music with correct time signatures, delete time signatures” doesn’t seem TOO far from ideal when it’s an irregular pattern.
Dorico does have good support for what we call interchangeable time signatures, whereby you define a set of time signatures at the outset, and each subsequent bar may be in any of those time signatures without the time signature itself appearing. When you stray outside of the set of time signatures defined in the set (or explicitly set a time signature as being the end of the interchangeable sequence), all of the subsequent time signatures appear by default once more.
This is simply amazing. Is there anything you guys haven’t thought about?!
How about irrational meters?
Did I stump you yet?!
You can define irrational meters like 3/6 etc., but the missing component at the moment is the ability to specify the metric modulation between the previous rational meter and the new irrational one. This is also the main stumbling block standing in the way of our supporting polymetric music where the beat lengths between different simultaneous meters don’t coincide.