I sympathise with the problem (and pretty much agree with your proposed solution), but it has got to be remembered that Serco aren’t starting from scratch – they’re bastardising the Bixi software which was designed for a much smaller scheme.
Whilst it would probably be a good thing if they threw away the software & designed something bespoke, that’s not going to happen (the costs involved would be prohibitive). So what happens? They’ll no doubt continually try to tweak the software so it can cope with the volume of data that’s being thrown at it…and hopefully throw some new hardware at it.
I was at a conference/sales event last week where a server was mentioned with 10-core Intel CPUs and 5 Terrabytes of RAM that was dealing with something stupid like 7 Petabytes(sp?) of data in ridiculously small amounts of time. I’m sure one of these would help!