Limited recording channels. Unable to record catch-up.
Why is the TiVo box limited to 3 simultaneous channels it can record at the same time. It can clearly access on demand services and stream these through the box to the TV. Therefore it should be able to record them by saving the stream to disk rather than putting it out to the TV.
Given this, then 1) only one tuner is necessary to allow watching a particular channel in real time. And 2) an infinite number channels could be recorded and saved from catch-up.
This would simplify program recording - as there would never be a conflict and all the silliness that goes with it. Obviously the processor and bandwidth restrictions would mean that only a few simultaneous channels could be saved at any one time. Given you can go back 7 days, then the box can catch itself up as resources permit.
Now other suppliers such as Sky and BT and Apple appear to be able to do this. Virgin Media need to get up to date or people will get fed up with recording issues.