My wishes also mostly about the tester. When you have tested things using your own framework, it's a pain in the ass to use the very limited mt4 tester.

Some improvement suggestions would be possibility to test strategies on multiple currencies at the same time, possibility to have one optimization period and one verification period, no limit on parameter combinations and better optimization strategies for genetic algos like possibility to optimize for combinations of results (50% profit, 50% profit factor) and there should absolutely be a possibility to optimize for consistency of results (based on distribution of results from different orders)

edit: and my main wish would be working Linux version and to be honest that would be that they would throw away the whole mqlX and just would give a standard api for java (or c/++, lisp, erlang, ocaml, ruby or anything because there are a lot of mature languages already so there's no point in trying to create your own). Oh and add a decent scoping too, it's absolutely crazy that inner scope variables are available outside the scope too.