No not really. He can't dive down quick enough anymore in an era where most strikers know the best shot is the low driven one.
Yep. He has gotten a good deal slower in his reflexes. He does good when he has got time like eg against Aguero, but overall he is too slow to get down by now.
Oblak made some ridiculous saves against us in the EL final, iirc, that were all about quick reflexes, getting down and in a corner fast enough. Cech cant provide that anymore.
His big big strength remains his big body and box control regarding high balls, but it's not enough for the top.