because ugly as sin, less functional, and terrible themes aren't enough explanation? And I know they say it has lost no functionality. in technical terms, that may be true--it can do all the things it could before. it just takes three times as long, and six times as much effort to do it.
In the name of simplicity they added complication. in the name of functionality, they removed function. In the name of taste, they made crap. and told us it was for our own good.