Every pilot when told nothing more than "remain outside" should respone with "request onward clearance time". ATC are required to provide it. Just like an EAT it is not optional and has a number of important consequences for both ATC and the pilot
DFC, you really need to come and see how ATC works, for real, not in simulators.
Sure whenever I tell you to Remain OUTCAS is could give you an OCT, but I will give you one that is 30 or 30 minutes away, because I know that I will be able to fulfill that obligation.
What I could not, and therefore would not do, is try to give you one with 'accuracy' - free-flow from the numerous TMA airports means that you get your clearance as and when we can fit you in - when you have a departure screen full of pending departures that are taxying, it is not always safe, or prudent, to give clearance to some crappy little aircraft tha climbs and flies ridiculously slowly.
You will get your clearance, but when I (who has the full picure, not some TCAS induced supposition) deem it to be safe. If you are a jet with good climb performance, you will get that clearance quicker because using my skill as an ATCO I know what will work. All your talk about ATCOs who only do it one way is utter tosh - the reason they are ATCOs is because of flexibility and their ability to change practices depending on numerous different scenarios.
DFC, please visit an ATC unit and start some dialogue - you will learn something.