If anyone smarter than me sees anything wrong with the conclusion I’m drawing here, please let me know. I’m pretty sure this is accurate and my testing confirms it, though.
The F-MK speed buff (from 13 frame startup to 11 frame startup) seems to have also buffed Oni’s F-MK Kara Throw range. Since Oni’s F-MK range is the same but the speed is faster, he must now be moving farther PER-FRAME than he was before. This means that now F-MK is his best Kara throw (instead of F-HP).
The GIF below is the resulting distance after a completed Kara Throw on a Recorded PC at the start of training mode. Green PC is Ultra, Red PC is AE2012 (look at their left-most foot).