The A380 wake issues should be mitigated in the future with RECAT, and of course even today there is no wake separation required between a pair of A380s, which is not the case for two Heavies on approach: So the benefits of A380 ops will increase if a critical mass is there, even if just over a period of ten minutes or so.
Where did this 1% of LHR traffic figure come from? It's more like 3.5% at the moment, which is a lot more significant.
Great idea at Hounslow international, trouble is, invariably at OMDB we run into wake issues following a super, usually as a result of the perpetual quartering 10kt tailwind all the way down the approach. We normally strike the wake between 500-300 AGL, and it's the cause of numerous weekly GA's.
It doesn't seen to be as much of an issue following a 400 or 777 and bizzarly the worst non 380 wake I suffered from was produced by and A340!