That could easily see similar pax throughput as Doncaster, Durham Tees, Norwich, Humberside etc.
The last thing this country needs is another high capacity airport (a la DSA) opening struggling to break even. If PLH is closed there is no hope in another one opening nearby: There are other airports. Who is going to pay to build the new airport? and... NIMBYs.
Once PLH goes, its gone for good I reckon!