Whilst I feel nothing but sympathy for everyone who has had the rough end of the AT service I cannot resist tackling one of the ideas often proposed by the critics. Let's assume that the MoD takes this pearl of wisdom to heart and completely bins the in-house AT capability. Does anyone really think that any money saved would be then spent a higher-quality charter service? In reality, I am sure that any charter will invariably be awarded to the lowest bidder and so any improvement experienced by the end user depends purely on a company who happens to have nicer aircraft winning the contract. Furthermore, the MoD is such a poor customer that any first-rank operator would either not bid, or quickly lose interest. Without any in-house capability the charter firms would have the MoD by the balls and they would know it. Your guess is as good as mine as to effect this would have on the cost of lowest bid. Thirdly, charter companies will not and cannot fit DAS as the equipment would not be released to them by the DoD and it be would outside the civil certification of their aircraft. The crews insurance companies and unions might have a say in this area as well. Finally, and most importantly, all but 3 of the current fleet are also tankers - a capability which cannot be operationally chartered.
By the way, FSTA is also primarily a tanker and the low number of airframes means that AT will not become any more convenient.