This is another example of bad English.
A leap is a forceful jump. Normally ones says a big, huge, great, phenomenal leap. Radical is not the correct adjective.
Radical means "characterised by a significant departure from tradition; relating to or affecting the fundamental nature", as in a radical change, a radical overhaul, radical reforms, a radical proposal.
"a radical leap in ability" is definitely bad English. Don't use it.