The 20dB (100 times) attenuation that are common in scanners are way too much for me. I would like to see 6 or 10dB (10 times) alternativ. It would be easy to modify yourself if the components wheren't drenched in epoxy.
It would be nice if a scanner had two antenna connectors and each channel could be set to select either one. Users now have to use compromises with multiband antennas, filters and combiners to try to get any decent results. It would be much easier to have one VHF and one UHF antenna connected, or even one multiband and one directional antenna for special cases like simulcast problems or one distant system that you want to monitor. There is also the phenomen that if you move your chimney antenna to the other side of the chimney you get better reception from some sites and worse from others. Having an antenna selection with each channel will get you the best reception.
/Ubbe