Worth remembering PIK's terminal was taxpayer funded and built for long haul. It's not really ideal for the Ryanair operation which could be run from a much smaller purpose built tin shed.
If the money was there the whole terminal could be demolished along with the old cargo bays and a much smaller modern building put in it's place attached to the rail link. However the return on that investment may well be near zero as the main tennant would never agree to it. The interior of the terminal looks fine landside, however the exterior is utterly lamentable and shabby, with airside facilities that were built in the mid 60s and haven't been changed since.