I'm not really going to comment on normal recoveries that are too good, I just think tether recoveries in general are a bit silly.
1. Some tether recoveries are really good, sometimes too good. The worst offender of this is Lucas, because he has access to PSI Magnet and his tether, and the combination of the two covers a lot of distance and risky to challenge in the air.
2. Some characters are noticeably worse at edgeguarding against tether recoveries. For example, Marth has no real answer to tether recoveries because people who use tethers can dip below the range of an f-smash and snap to edge quick enough to avoid an aerial punish. Plus, the air dodge > tether prevents people from going off-stage for a gimp/edgeguard. The common argument is that they could just wait on the edge and have them pop up in the air for a punish, but since they know it's coming, they can DI towards the stage (because, let's be honest, even if you receive damage, EVERYBODY would rather be on-stage than off-stage) or DI up if they get sent off-stage for an easier angle for recovery. It's even quick enough where you can miss the punish if you miss the timing. I think this is silly because if you look at Melee and even Brawl, almost every character, even a lot of the bad ones, had an answer for nearly every recovery. The tether system we have now is unbalanced because there are some characters who literally don't have an answer for tethers and that's bad.