Yes, I think they are very useful.
You could have different arrangements that use the same loaded instruments which could also be saved as a rack (meaning saving the whole vst instruments (F11) rack and even saving the state of the mixer would be awesome rather than having to recreate from scratch.
Imagine: you have your orchestra set up as you like it and just add another arrangement (like you are going to make another movement/take/variation) nothing to reload!!!
Like a workspace only more powerful…
one can only ask… 
Cheers
Javier
Just open the old project, rename, delete all parts and make another arrangement.
Sure it is a work around some situations.
But when writing some stuff you may want to have more than one arrangement open and copy/transfer stuff between them. Specially more classical stuff or when working versions of an “arrangement”.
Yes you can have more than one project open right now, but if you have quite a few instruments loaded it takes a while to “activate” and switch backwards and forwards.
It was just a thought since it used to be there.
I think projects are great but I would also like to have the arrangements back -not instead.
I would like something like this, but I would also then request that you can insert arrangements into other arrangements (like video sequences can be nested in say Premiere). This would be most useful for composing to video because it would offer a way of mixing and overlapping different sequences with different time signatures all on the same timeline, something which I always have a lot of hassle with.
Mike.