I agree most of his signings were shit. But they were more often than not pretty cheap.Rafa bought some amazing players but overall adhered to a rather flawed transfer strategy that ultimately cost him his job. Very frustrating guy.
As for why we are so shit, a big reason for me that I don't think has been highlighted yet is that the club is stuck in this awful situation of trying to keep up the pretense that it's still part of the elite few when in fact it's not.
We can't quite get the top players so when we make statement signings they're riskier or just plain stupid.
And when we buy young players we can't quite afford to let them learn on the job because of the expectations. Even Sterling who is a world class prospect was getting shit early on, which I always thought was mad... not in the least because his performances were never that bad.
There is only one way out and that's inspirational management from top to bottom and we haven't had that in a looooooooong time.
You have to ask yourself why he was "forced" to buy those types of players as well. I feel as if he was trying to cover several positions with a pretty small budget.