To be fair I'm quite critical of Reina but I don't think there's much he could have done against that Aguero finish, it was just an unbelievable goal. I have teased a bit but that's just because people seem to pick on De Gea a lot when he hasn't done much wrong either. Hart makes a lot of errors as well, but like De Gea he makes up for it with his shot stopping and other qualities.
There aren't many goalkeepers that genuinely dominate the area and deal with crosses effectively, and even the ones that do often have weaknesses in other areas like reaction speed, agility and shot stopping ability (often because they are bigger/heavier and therefore slower guys).
It's swings and roundabouts really. There are probably 5 or so goalkeepers on the planet that have it all and they would command a very high pricetag. Some of them are also close to retirement.