An ATCO cannot be expected to know the performance limitations / handling characteristics of every type of aircraft. However, the pilot of an aircraft should have a great understanding of their aircrafts limitation / handling characteristics. If given an instruction that would place the aircraft outside the aircrafts or the pilots limitations then it is up to the pilot to say that they cannot comply with the instruction, no matter how experienced they are they should know when to say no.
The lack of new ATCOs aircraft knowledge is a problem, but they will learn given time. Give them a chance, we all have to learn.