@.AC.
Since you randomly selected D3 and Snake to hate on, I'll give props to both of them.
There are good things to be said about what D3 and Snake do to the metagame (each can be counterpicked, for starters, and the viable counterpick list is very nonlinear in the tier list which is cool, too, and notably the counterpicks for D3 are not the same as the counterpicks for Snake, which makes the network of characters even more interesting).
There are good things to be said about what D3 and Snake do to the strategic situation in the game (with D3, if he chaingrabs you, clever usage of platforms can keep you safer, but you might not always want to do it.. the decisions are complicated. Snake's stage control with explosives is probably the most interesting strategic dillema presented in any smash game so far.)
There are good things to be said about what D3 and Snake do for making the game more exciting (think of the cheering that occurs when D3 lands a mindgamed sweetspotted FSmash, or when Snake breaks a shield and sets up a Wargasm, or when Snake is grabbed out of his cypher and needs to c4 recover.)
MK pretty much fails on all those fronts (and more factors could be considered, but this is already long enough.)
Whether he improves the diversity in the metagame isn't argued, the amount by which he reduces it is.
Strategically, MK is a light character with instant, combo-stopping, safe attacks, who cannot really be attacked offstage, and isn't any worse on the ground than in the air, and isn't any easier or harder to approach from the front vs the back vs the top vs the bottom, and never has to worry about landing with so many jumps and a plethora of safe ways to land even if he does choose to fake out his landing so many times that he runs out of those jumps... the list goes on. Point is, he's never any better or worse off in one situation versus another. (The reason he planks/scrooges/air camps off stage so well is because most characters lose the majority of their options when going goes offstage.. MK isn't affected.) Strategy basically doesn't exist for MK; any strategy in a game with a MK in it is borrowed from the strategic interests of the character he plays against.
As for excitement, the only cheering you'll hear in a MK game is if people see him lose - at the tourney I went to more people watched the all items on free for all side event than M2K vs BlueRogue grand finals for the real tourney; in the middle of that match people started leaving; apparently the grand finals of an event they devoted their entire day to wasn't exciting enough to bother watching since it involved a MK who was going to win.
Edit: wow, too much posting. The post by .AC. I was responding to was like two pages ago now after I composed this response.
