Yes it's entirely personal project. When you consider cars though, we have rain sensing wipers on some new cars. Why? I have to look through the windscreen in order to see, so surely i'm going to notice this rain stuff getting in the way and all I have to do is turn on a switch. On the other hand, in my view, wipers have been flawed from the moment the wash was integrated with the wipe. In the old days, I had to press a manual pump (before I fitted an electric pump to the 1970's car I had) and if there was no water flow then I wouldn't wipe.
Even a lack of water in the tank is sufficient a problem enough to want to defer the operation of wipe action should the windscreen be smeared with road spray. So even a simple delay doesn't actually solve the problem. The fundamental issue is that for a number of scenarios, low water, frozen jets, bugs on the screen that you want washed before wipe - the correct action should be water first and if no water, don't wipe!
I agree, technically keep it simple however cars are a classic example of where things used to work without any electronics, now they are absolutely full of them from complex engine management, safety system ECU's, entertainment systems etc. such that even from a manufacturing point of view, there can't be a serious argument that introducing a pretty simple flow meter which would cost pennies to produce in order to put an inhibit and delay into a wipe system would be something to get concerned about.
Furthermore, there shouldn't be a 2 in 3000 risk of it introducing a stoppage of the wiper at a critical point because it would merely inhibit the wipe part of the wash/wipe. It's a different set of contacts on the stalk that operate the full time wipers so the correct circuit to break would be the wipe part of the wash/wipe, not the normal wipe.
Adding heated nozzles introduces another complexity and few cars feature those compared with all that are on the road so just like all these other toys, this is just another.
Anyway, as I said, it's a personal project so it's all irrelevant.
David.