I certainly wouldn't rule it out. Remember 4 aircraft for Jet2 is not nearly the same as 4 Ryanair based with additional non-based flying.
TUI are already heading towards 2 and 3 aircraft at BOH and CWL respectively and it's not unlike Jet2 to dwarf their presense elsewhere.
Did anybody really expect BHX and STN to each be 14-15 based only 3 years ago?