Here's an idea
Two crew transport, listening on 121.5 misses a call on comm1 because of someone "nattering" on 121.5 - as PNF is dealing with comms, why not have PF listen on comm 1 and 121.5, and PNF just listen on comm1?
Apart from that, most calls on 121.5 (apart from the afore mentioned burps, farts etc) seem to be ATC trying to find aircraft which are not answering on the correct ATC frequency. So what are these guys doing - they change frequency and get no answer so they just keep on trucking without going back to the previous sector to check - or it goes quite (which rarely happens except late at night) - and after ten minutes they think "this is nice and quiet happy days" rather than "gone a bit quiet I'll just check the squelch/volume control/ASP/ ATC are still there?". Coming back from ALC recently I heard Spanish air defence, Bordeaux and Brest all trying to find missing airliners on 121.5. - Surely 121.5 is designated as a distress frequency. perhaps we actually need a designated calling frequency for ATC, it shouldn't be neccessary to listen on the distress frequency over continental Europe to avoid being intercepted when we can't get in touch with ATC.