In an ideal, sensible world yes....but this is the army! so no!
in all seriousness though, stand collars would be a huge improvement. They always look smarter and more uniform when in a group.
i'd second a better material too. superfine's would be great if possible. again for uniformity overall. and i would keep the colour. it is after all the historical colour (or as close as) as the Irish Volunteers.
two things I'd suggest though would be different colured patches behind beret cap badge (have said this already some other thread) to identify corps. more relevant now day to day with DPM. and then on the SD trousers a thin strip the same colour running down the leg. in SD 1s individual units are identified by flashes and lanyards but Corps only by collar badges. it would add a little colour to the uniform without being too over the top. the Cav presidential escort has shown a little what it could be like with the red trim on their tunics.