I think 'legacy' is probably a typical mis-used word and part of the modern business speak that is so infectious.
Typhoon - new, entering service, cutting edge etc etc.
MRA4 - new (really), entering service (mm), cutting edge?
When we look at the GR4 and GR9 these are both newly packaged, like the Nimrod, in old airframes.
The F15E is also termed legacy.
Maybe legacy refers to the old-way of doing business and the new all electronic kit it the future.
