Rain receives a lot of un-deserved hate just because of that. I feel he's one of the better characters from that era of MK.
is not only by this, there is more reason for explain why him was hated
Yeah, you said that Rain was a failed character concept.
Rain was a good character in UMK3, and my main for that game.
I don't see why Rain is a failed character concept, just because Ed joked and named him after a Prince song?
One thing is talk about a failed character that for a long time did not appeared and other very different thing imo is talk about character fail- mentality.
Rain was not good character at umk3, but too have a similitude with the new character from original mk3, rain have a stupid martial coreography, also too generic
but with the huge difference that rain have an unbalanced and exagerated special moves.
Also with few sense of animations. Rain should not to have electrical special moves, but at least mk9 has fixed this lacks of realism.
Also again, horrible and generic, too his bio and his ending is few developed.
Rain was a failed character, cause him just is back in mk armageddon , also midway team has tried grow up to Rain, the only bad on him at mk ar, is that he use the same fighting style from tanya in mkd,
again you can see other generic example on rain

.
But again, the original rain was a whim from an utopic mind and this was from Boon nothing more and nothing less.