Lon More: the cause of the problems wasn't the number of squawks, but the fact that a short plan was made on a VFR squawk (erroneously having a Mode C of FL601) and due to their large numbers, this input has overloaded the correlation logic that didn't know which one to couple the short plan with - then it all went down.
I think the problem here (NL, BE, W-Germany) is the lack of "middle of nowehere" airspaces - wherever you go, you'll bump into a TMA, CTA, MTMA, TRA rather sooner than later.
I don't think Mode-S transponder is a solution for gliders either, but as a matter of fact they are a clutter also when they appear only as primary targets - and those ones are much more frightening for me than seeing that it's A7000 - at least from that I know that even if it hasn't got mode C it's somewhere "down below" our airspace.