Well, Green Lantern might be an exception because he is supposed to be one member of a whole large police force, so I guess it's natural to have other Green Lantern (I do find dificult to swallow that out of all planets in this infinite universe, many of them without a representative in the corps, there are 5 or 6 members from this little mudball Earth, and all of them are American). But I do think that anything that makes a character less unique and original weakens him. Take for instance Superman. Pre COIE, the "last son of Krypton" was as unique as fish in the sea, with super-boys, girls, babies, dogs, cats, monkeys, horses, criminals, an enlarged ciity tiny survivors and so on... Added that to the "super-everything as was required", Superman was never really in my must read list. Mostly read him in Justice League (though I did take an occasional peak in the Wolfman/Kane run that came shortly before COIE). Then came in John Byrne, and did a hell of a lot more than trim the fat. Superman went back to being unique and truely "THE LAST SON OF KRYPTON". There was no one else around like him, and that made the character sooooo much more interesting. Plus, creators really had to be creative when bringing back proprieties that had been erased by the universal change. Supergirl was now an other-dimensional artificial being. Superboy was an attempt of cloning Kryptonian DNA, merging it with human. Krypto was actually a normal dog belonging to one of Superman's greatest fans. The Phantom Zone criminals were from another dimension, and so on... Of course, as has been mentioned here, comics seem to move in circles, so it all eventually got brought back in one way or another, and Superman went back to being just another face in a large crowd of Kryptonians (I honestly have to confess that I have no idea what's it like now after the New 52. I know a Kryptonian Supergilrl is around, but not much else).
I do find interesting the angle of Ross becoming a monster like the one he always hunted, however I find a "RED Hulk" really unoriginal. Couldn't they have given him a different design and called him Red Zone, Condition Red, Defcon 1 or something else? However, as I've said, comics go in circles (nowadays, it seems, more than ever, with writers and editors not giving a crap to what the previous writers did and changing everything to suit the story he WANTS to tell, so that the next can come along and do the same, and the next, and so on...), so I guess someone will one day bring back Red Hulk Ross and maybe even the others...
Peace