It was a "universal fact" because he was really popular for a while and when played by experienced players (Loda, BurNiNG, Sylar...) who've possibly played hundreds of games on him over the years he can make impressive performances, much like any other carry. Still, being a carry with no real rightclick steroids, medium range, medium mobility, little CC and a high amount of farm needed to do decent physical damage in a fight it is kind of hard for me to find out the element of "overpowered" in that hero. His only strenghts are/were in survivability and snowballing when your team had early-mid game advantage and holding onto it before enemy no-farm weakling supports could recover from his fast eblade.
The actual universal fact was that for whatever reason people were pissed at Morphling for being picked in almost half the games in TI2. I watched every single tournament stage game and some 65% of the preliminaries and read a lot of forums and reddit between the games and there were cries of "Morphling OP" everywhere after LGD shitstomped yet another Western team with Morphling - put it anyway you want, but on a hindsight I'd say they would have shitstomped with any other carry, like they did whenever they didn't even pick Morph. And Morphling winrate was 58%, which is admittably high until you consider a lot of those wins are Chinese teams stomping Western teams, which again they probably would have done with a different draft. Did LGD go 18-0 because they knew Morphling was OP, or was Morphling just an innocent victim when LGD were OP?
As of now, Morphling has the lowest winrate (in the current version) of any hero in the history of dotabuff.com, he is never picked in competitive and his Eblade builds are crippled by the awful cast times on his abilities. I'll give it a year or so when people forget how they used to hate him for whatever reason and start demanding buffs.
@Kuntantee I don't really agree with your style, but you do have a point. I'm however afraid that that point has already been made several times to no effect. I've tried to but failed to get a hold of whatever his perspective is, but at least I'm still being amused at by how after 6+ years of dota he is the first person I've heard suggest that Stormbolt, among a slew of other things, are somehow OP.