What absolute and utter tosh.
The modern Hawk (LIFT/127/128 etc.) is an excellent trainer for any modern fast jet pilot, if expensive.
Despite a high price tag, Hawk has won trainer competitions again and again, and deservedly so, and the RAF's selection of 128 to meet the AJT requirement is a rare example of common sense over narrow bean-counting.
The relevance of the T-50's supersonic speed capability can be guaged by the amount of supersonic sorties in the current USAF T-38 training syllabus.
Apart from the issues referred to by Clockwork Mouse, above, one might wonder whether the UAE has calculated that one of the other candidates represents a better dedicated trainer for its 80-strong fleet of F-16E/Fs, or perhaps whether the decision reflects the muddled thinking that saw them cling to the dual-role trainer/light attack Mako for quite so long.