A couple of things:
-Single-Player: It is arguably the worst mode of the Smash games this time around, with 8-Player being the biggest form of Fake Difficulty the series has faced in a while. Master and Crazy Orders both are extremely stacked against you and offer some of the dumbest options for matches that it's not even funny.
-The Challenges: HOLY ***, the CHALLENGES...if they're not tedious grind fests, they're insanely specific events that either force the RNG to be in your favor or challenges that actively force you to deal with outright stupidity.
-Stage Selection: Unique stages are nice, don't get me wrong-Omega stages were both a blessing and a curse to some extent. However, that doesn't exclude over more than half of the stages from criticism from sucking so badly (The 3DS had too many stages that transformed/moved, this version has too many bloody hazards that define "Fighting the stage, not the opponent(s)), with GCO and PT being the best examples of downright mental *** in terms of ideas. That, and the lack of a Hazard Switch is asinine...
-Online: For Glory sucks (Cancerous players), For Fun sucks (Even MORE Cancerous players), and Tourney Mode is beyond disappointing, what with its limited options that make the previous two games' tournament modes seem like quantum physics by comparison, and the Official Tournaments are so limited and broken that it makes you envy those who can actually get into a 1v1 room. That, and Omega Only stages is a massive problem...
-Smash Tour:................................................................................................................................................why, Sakurai?
All of this whining and *** aside, I do thoroughly enjoy the game, because let's face it-none of the games are perfect in any way, not Melee, not 64, and CERTAINLY not Brawl...