This ought to be pretty easy to sort through with a stat pac and some patience, which I and most of us thoroughly lack.
That being said, I suspect Self's more talented teams had just as big of winning margins (both average and standard deviations) as Self's.
Self's problem since 2009 and onwards has been that though he has signed quite a lot of talent some seasons, mostly he has been recruiting against a stiff current that has denied him nearly as much talent advantage over Big 12 teams as Roy usually had during his KU tenure.
You can't blow teams out frequently, when the talent gap between you and other teams lessens, especially in the injury riddled seasons.
And let's face it, gang, KU has been snake bitten with recruiting adversity and operable injuries the last 3-4 seasons especially, which is driving most of the remembering going on in this thread.
The combination of Self recruiting:
No projected OAD post men;
Increasingly short adidas stacks;
No projected OAD point guards;
Frankly weaker and weaker backup bigs; plus
lots of operable injuries to starters AND backup rotation players; and
frequently early departures that Roy had to contend relatively little with....
has left Self in a strategic position where playing to keep it close with injured players and a shrunken talent gap has made it tougher for Self to blow anyone out.
So: yes, I suspect there are fewer blow outs under Self, but I believe circumstances of recruiting and injury, especially recently, have channelled him toward a play it close strategy recently, and selective memory emphasizing the recent is exaggerating perception of the real phenomenon.
And remember that when Roy finally brought his system back to Chapel Hell and got greater numbers of good players each season he won a couple of rings pronto, while continuing his intermittent blow outs and getting upset.
So we have complexity involved here in the drive set producing the outcomes of both coaches and we have selective memory focusing on recent Self and late Roy.