Northernsky,
I think you'll find that the original source of this thread was not the querying of an instruction, ie "is that when ready?" but the acceptance and readback but non compliance with an instruction to decend. Sure it can be annoying if you query something but if I mean descend when ready, I'll say descend when ready. That is why we have standard phraseology.
As for "
The majority of descent instructions, in AC at least, should be 'when ready', if the controller is planning properly and has good understanding of aircraft performance and profiles." it shows your ignrance of what we do. Just try figuring in two or three minutes of "compliance time" on every descent clearance, coupled with normal jet cruise speeds and calculate the distance involved. Now try to fit a significant number of aircraft into a restricted amount of airspace containing numerous crossing (and conflicting) routes, everyone asking for direct routeings, a few active danger areas and maybe some weather for a bit of spice! Then throw in the wildcard - the non-responding crew or worse, the non compliance with a clearance (be it speed control, descent or whatever) and our separation minima are long gone. Most of the time, we let it go. Occasionally, after several "hairy moments" caused by any combination of the above, we get a it antsy. At times, we have a very hard job to do and the last thing we need is the "artistic interpretation" of a clear and concise instruction to throw a spanner in the works.
On to your complaint about direct routeings. How direct is direct? Next waypoint? International FIR boundary? Commencement of STAR? Destination? How the hell are we supposed to know where you want to go direct to if you don't ask? I for one am more than happy to clear you direct to wherever I can - but I cannot read your mind, almost certainly cannot clear you direct to destination, so which intemediate point am I supposed to pick?
ATC is a service industry. We know that. Some of us pride ourselves on trying to give the best quality of service that we can. We also try to do so as courteously as possible. At times that becomes very difficult when the guy at the other end of the link doesn't keep his part of the bargain.