No, changes do need to be made, just not this drastically. ODi series should be shortened to 3 match series, these 5 and 7 ODi series and triangular tournaments are ridiculous. You could then have 1 or 2 T20's alongside the 3 ODi's. This would cut down the ridiculously packed player schedule, which I believe would improve the overall standard of cricket played. We also need to stop having a T20 WC every year, it's pointless, completely takes away the achievement of winning a WC if there's one the next year. The Test countries boards also need to be stricter on their contracted players, stopping them going to the IPL if they're carrying injuries or have a particularly busy schedule in the near future.
Also there needs to be some sort of fining system in place for the National board if they consistently produce god-awful, flat slow pitches. The reason pitches are getting flatter is because of the money, so if you fine a board for a shockingly flat pitch, they'll soon incentivise the domestic groundsmen for making a pitch that offers an even contest between bat and ball. Flat pitches producing boring Tests is what's going to kill Test cricket, and something needs to be done about it.
Day/Night Tests are a rubbish idea as well. The last thing I want to see is a Test match played in coloured clothes with a white ball. Eugh.
I was merely trying to say that 50 over cricket should stay as it is, what would be the point of taking away 10 overs. I agree with everything else your've said though. But where do you draw the line for fining boards if they produce poor pitches. I don't think that could work tbh, although don't they do it in county cricket.