The sl7 has a pretty deep sail.
I think we can all agree there's a bit of oversteer there.
Its actually not as deep as it looks, the keel extends forward of the normal location making it *appear* deeper but the angle of the outer sail half is shallow compared to some kites, thats one of the reasons it backspins.
But, I'd agree that in general terms deeper sails contribute to less oversteer barring other design elements contributing to it.
The Psycho and Stranger had relatively deep sails for their size (and time) but oversteer plenty.
Personally I quite like kites with a bit of oversteer and still enjoy hacking a psycho about - its quite fun to spinstall to stab etc. on a windy day.
Alan makes a good point about technique, going back to some kites I used to fly I'm horrified at how they oversteer for about 10m by which time I'm flying straight lines and square corners again, just need time to adjust.
Vive la difference, it would be a dull world if everything turned like a Nirvana