I am a big fan of short cage road rear derailleurs.
They are light, shifts better (higher tension), and has more ground clearance (which is important for small wheelers)
-You can use (mostly) short-cage road RD with 11-32T cassette.
I have experimented with even 11-34T one.. it worked well!
Shifting becomes sluggish when you move beyond ~28T range, but you won't use 32T very often anyway.
More option is always better I think.
-You can use short cage RD with triple cranks.
With this setting you cannot use some (usually 2 or 3) extreme gear combinations such as 53-27T, and you should avoid cross-chaining anyway.