I think an all encompassing fix is never going to happen. However, I have developed my own strategy for minimising the problem; I think personal awareness coupled with good lookout and use of all available facilities is the best way but there is no foolproof method.
Mode S on, TCAS (TAS) on, RIS/FIS whenever possible. Transit inside controlled airspace in preference to skirting round the edge of it. Avoid the airspace just below the cloudbase. Avoid choke points, climbout areas and approach paths (some intelligence needed at times if you aren't familiar) and don't overfly beacons if at all possible, VFR or IFR. Use the second radio to listen to minor airfields en route, even if keeping well clear of the ATZs and do speak up if relevant, provided it doesn't adversely interrupt the ATC service under receipt.
A couple of things I have noticed in my thirty odd years of flying:
Some pilots don't speak up when relevant. For example, pilots operating in the circuit where there is no ATC (or leaving or about to join) seem reluctant to answer a call from a passing aircraft and simply plod away giving standard circuit calls and nothing else. Calls such as "Two miles south, approaching the overhead for join", or "Climbing 2500 ft and departing west", or even "In the circuit, remaining" might be a very sensible type of call to make in reply, allowing us all to build a mental picture of who's about.
Some pilots don't make full use of their transponder. This is increasingly important in the days of TCAS equipment; everyone flying with a Mode C transponder should actually use it, 100% of the time! The most silly remark I've heard in respect of this is "Why should I bother, when I'm not getting the benefit?" Everyone gets the benefit because the pilot of the TCAS equipped aircraft coming the other way will get advanced warning, rather than relying on his/her lookout at a much closer range. The paradox is that pilots who believe their lookout and "see and avoid" is foolproof might actually be the ones most at risk; they don't understand the limitations of the human eye and habitually miss seeing many other aircraft. They relax in the false belief that the sky is less congested than it really is.