@cat: basically this leads to the discussion how often you want to enable/disable different parts in the graph. vvvv basically has two design strategies: the internal graph which is optimized to be really fast as soon as it is set up, and the graph building mechanism, which is optimized for flexibility and is not really optimized for speed.
so if you would use enos real-switch to replace a real switch and switch that every frame, performance would be seriously drop. so both strategies are valid, its just the question whether they should use the same user interface or not.
anyway the best option for users would be having the graph automatically know what needs to be calculated and what not. as gregsn explained, we see quite some possibilities to eliminate superfluous calculations, which could be done completely automatically - i agree this should be one of the next big steps.
@u7: the problem with trees is obviously that you can and will join things again upstream - which will make things difficult to trace (when not having the potentally performance hungry visual highlighting mechanism) - so a visually simple model with one-enabled-per-patch or permanent selections might be preferrable. but your solution might be much easier to implement…