No, it is absolutely a staple of her match up vs us. Granted frame data isn't fully out yet, the move is still frame 4-5 out of the special hop. Frame 10ish from mid air.
If Corrin does it instantly out of that hop, she will pin the ground. From what I can tell, you cannot OoS punish her when she pins, because the kick is really damn good and can be used while retreating to make her marginally safe (IF NOT COMPLETELY SAFE.) By the way, the kick is also a kill move, so it doesn't really matter if she gets the tipper in this case. Bottom line, she's only punishable if she isn't sticking it in the ground, and if you try to attack her before it comes out you risk eating FAir chains or immediate spear.
Ike and DK aren't characters with amazing mobility anyways. Their stats are solid at best. The problem is the threat they pose when they get in a certain range. I would argue the threat that Corrin poses in her optimal range is MUCH higher than that of DK/Ike, grab shenanigans withstanding.
So it comes down to making sure she doesn't close that gap, but she has very potent and damaging spacing tools that make your spacing tools very risky in a certain range. BAir is fantastic, safe, beats many of M2s options, and does good damage/kills. FAir is quick, beats many of M2s options, does good damage and combos into more FAirs and TIPPER SPEAR. (This is thing that works and kills Mewtwo center stage around 70 no rage). Spear we've talked about.
Not trying to be a Debbie downer, but we really need to be prepared for the matchup as more people develop this character.
EDIT: For reference, here are some vids of the match up, vs a top player in our scene. Keep in mind that this is essentially the very first time I was playing this match up, so I'll admit to doing a lot of incorrect things.
However, it's also the first time he was playing this match up, so take that as it is.