Originally Posted by Life's a Beech
In fact, one of my pet hates is being told I can't descend because it would take me into uncontrolled airspace, I must wait x miles
Perhaps a "...request to leave and re enter [if you do re enter] controlled airspace on descent" might work?
ATC are obliged to provide descent that will keep you in CTA (and provide terrain protection), except in a couple of circumstances.
Though many ATC are aircraft enthusiasts not every one will know intimately the limitations on your particular aircraft. So without a reason or request otherwise, they will keep you in CTA.
This is a great example where visits and or phone calls will help grow understanding on both sides. If you had rung your local ATC shop and said "hey you know when I usually ask for descent before the next CTA step you guys always say no. I really need descent 'cause of my acft config, is there a way I can ask so that it will allow you guys to issue the clearance?" They may well have said sure just say ..., or given reasons why they CAN'T, not won't.
It is all about communication folks.....