your not the one getting vectors and descents that haven't been planned for..thanks for that by the way...
That's called tactical controlling, and no matter how much you plan for it, you may still get "unexpected" vectors and decents if the "big picture" changes due weather, blocked runway, Nav/Approach aid unserviceability, Emergency traffic et al.
As I understand it, the human element is still in the cockpit and in the Air Traffic Control Centres/Towers as a higher degree of flexibility is required than leaving it solely to computers to carry out pre-prepared programs.
May I suggest that too much information may be a bad thing, as if the unexpected comes along, this is going to generate confusion, conversation and debate on an already congested frequency? Standing agreements between controllers are there for ATC purposes, and may be varied by co-ordination at any time! (Along the same lines with a CTOT. The -5, +10 mins is there for ATC
TACTICAL use, and shouldn't be used by crews to plan on. Some crews don't half get grumpy when they miss a slot by starting at CTOT +5 ,when they are fully notified aware of the slot either from GND or Ops, only to be told it is impossible to get them airborne within the CTOT tolerance due to the outbound queue!)
Nooooo but it would also help us with our "tactical" picture and planning to have some idea of what kind of descent or whatever it is you decide we as "customers" require
The standing agreements are there to ensure that traffic is presented to the next ATC sector in an acceptable fashion without handing over each individual track.
They are not there for crew descent planning, or to plan arrival/departure routes. That is the purpose of a SID/STAR. Most SID's and STARS are designed to take into account of these standing agreements i.e. the FL260 restriction at MARGO heading up North. If the restriction is not required, then Scottish will normally remove it on the RT then allowing the aircraft to fly their optimum descent profile to their cleared level. traffic then has to be presented to TMA airfields at or above Min Stack Level level by the final hold on the STAR.
There may be many things that do not directly affect your flight that mean you must be at a certain level by a certain point (traffic in/out of adjacent aerodromes, activated danger areas, co-ordinated airspace with the military, CDR's yada yada yada).
I would advocate that you do not query instructions given by ATC over the RT, or question the rationale behind it. If it affects you as operators to the degree that you infer by your Ops department not planning in sufficient fuel to take tactical ATC instructions, either file a Safety Report, MOR, or raise it as a safety/policy issue with your ops department.
We are not some secret society trying our best to push you round the sky for no reason. Again, use the old telephone call or take a couple of hours out of your day to visit your local friendly tower and/or Centre!