Well to DK's defense in the 3.5 patch there were very few characters who did not get nerfed. I play DK in all games and DK isn't the best in all the smash games, but I wouldn't neccesarily say he keeps getting worse and worse to now where he's at a level where he shouldn't be taken seriously. DK is actually a scary character in Project M, especially depending on the matchup. DK has a top tier punish game thanks to his speed, raw kill power and grab set ups and against characters like fast fallers and semi fast fallers one grab could mean death. A great example would be Poob or Strongbad's DK, who generally make one grab lead to at least 50-60% or even death. Also I don't feel like a lot of the changes in Smash 4 made him a significantly worse character, but I would say Brawl DK was the best incarnation of DK in an official smash game. The rest is up for opinion, but I feel like DK should never be taken as a joke no matter which game you are playing.