I think Link is being underestimated here. Almost everything about him has been buffed from Smash 4, in particular his mobility. Link's range was somehow improved which coupled with his increased mobility makes Link able to rely on his sword normals more to space his opponents out and do it more effectively then he ever has.
Then there is his edge-guarding and ledge-trapping, two things he was already at least decent in during Smash 4, being improved significantly by 2 things: the new mechanics and his brand spankin' new Bombs. This thing gives Link scary coverage when it comes to both edge-guarding and ledge trapping and it forces the opponent to try and think of so many decisions on how to avoid the bomb and either Link already has them killed or has an option for everything the opponent tries to do:
Opponent uses the get up attack: Link shields the attack and throws the opponent back, starting the process anew.
Opponent lets go of ledge and double jumps to attack: Link detonates bomb and they die from it or get sent in a position where Link has the advantage.
Opponent dodges bomb mid-air: Link punishes the lag with a down air spike which almost means certain death, even if they catch the Bomb.
Opponent Up B's to recover: Link's sword normals beat most recoveries and the bomb covers a lot of space which increases stage spiking chances.
Link has access to so many options in terms of edge-guarding and ledge-trapping that it makes him one of the scariest characters in the game in the corner because one screw up against him and you're getting edge-guarded by one of the scariest edge-guarders and ledge-trappers in the game with the amount of options and amount of coverage he has from just his bomb. And because he can Z-drop the bombs to recover, he doesn't have to completely fear going deep for the kill. Heck with the bomb, he may not even need to.
However, that isn't to say that I don't acknowledge his faults either. From what it looks like, he is susceptible to pressure quite hard and unless he can pull of a parry or tech a grab to rest to neutral, Link ain't getting out of pressure easily. He also seems to continue being combo food due to his weight and attributes so his disadvantage state is bad.