IMO, Ada should apply strict rules regarding implementation of the standard. Long ago you could not call a compiler Ada compiler if you did not implement all Ada standard.
As for pragmas, that is no so simple. Some pragmas are more pragmas than others, e.g. pragma Atomic, pragma Import, representation pragmas etc.
The problem is that both pragmas and aspects (the difference is in the syntax only) can influence the semantics or be just a compiler hint/correctness annotation. You cannot ignore them in the former case. If only the language clearly separated the cases…