Over wordy descent clearances, such as coming North towards Avant the clearance is normally 'descend FL 250 to be level 10 miles before Avant'. It's always very busy through that bit of sky (I once had to wait 4 minutes before being able to check in with London there), so why not say dexcend FL 250 level by Susix' [which is 10 or 12 miles South of Avant].
100% agree. There are lots of restriction like that. I guarantee you the controllers are just as annoyed as you are. R/T congestion is a major problem. Some of them are in the process of being looked at, and altered hopefully.