The anecdotes around Shulk.... so so so so so many top level players using him and completely and utterly disregarding them, followed up by using other characters sometimes (at least at that stage) considered average and do significantly better...
Trela: Brawl Lucario hero who slayed king of the mews and was unbeatable in the anubis strategy. Used Shulk early, lost a lot, switched to CHARIZARD (way way way before buffs), default Mii swordfighter (also way before buffs and everyone considered him the single worst character in the game), Mewtwo etc etc and was able to WIN
Gnes: One of the greatest smash players of all time, Brawl MLG champion. It's this guy's fault Meta Knight learned to play "gay". Anything lame Meta Knight was known for in Brawl, gnes was the guy who had to deal with it first (planking time outs, scrooging time outs, so on and so forth). Has used Shulk since early on in the game despite having very strong top tiers under his belt. From what I gather he's almost completely given up on Shulk at this stage in lieu of Mario, Roy and others. In times of Shulk, he would sometimes not be seen in top 6/8 of locals.
Ally: Another one of the greatest smash (PM, Brawl, S4) players of all time. Could not beat other players at a [assumed] lower level using terrible characters (at the time). Actually did more with Marth and Falco.
9B: The reason Ice Climbers killed Brawl, one of [if not] the greatest competing smash scientists of ALL TIME. Could not pull any results whatsoever with Shulk despite all knowing and respecting how good he is, could not ever breach top 20 at tournaments. Switches to Ryu and within a month or so is getting top 8 at major international events.
Shulk sucks.
Straight up.
On wifi the pacing of the game (and the stupidity of sh/fh air dodge) stacks up a lot more in Shulk's favour, allowing him to freely set up monado cancels or play passively when pressured and get out for "free".
But otherwise, he is undoubtedly trash. And I really don't know how one would fix him either, all his mechanics are gimmicky/unique (or at least non-standard), and in theory if they were more applicable he could be "broken"... that and considering his wifi strengths I'd rather think he shouldn't be getting mechanical buffs (which he would need to actually be good), and buffing the normals significantly ala Ike would either not be healthy for the game (i.e. Shulk reaches: "very good character without ever needing to use monado arts!") or they are of little consequence when fast, disjointed attackers are out there who can do better in just about everything he wants to do.
Like Jigglypuff, who has taken time for players to get why she's bottom tier (because she doesn't really have any notable deficiencies and she's very solid on wifi), people need to wise up on Shulk. Unlike Jiggs, Shulk has had numerous amazing players give it their all and failed significantly.
I'm more scared of a Samus or Zelda in just about every single match up.
Shulk is not viable. Possibly the furthest away from viability than anyone else in this game.