Pace is determined by personnel.
For example, with a big guy like Withey or Aldrich, having a fast pace doesn't play to your personnel because you're just wearing them down by having your offense fly up and down the floor, and you aren't taking advantage of their size because you're pushing the ball up and down.
So the question when it comes to pace is does a faster pace fit this upcoming season's personnel. A quick scan of the perimeter guys says it probably does. For one, we have depth at the point if both Mason and Graham can handle primary ball handler duties. I think Frankamp probably slides more to the 2, especially with Graham here, as having a bigger PG to allow Frankamp to play on the wing while still not having to defend a bigger guy is probably ideal. Plus, that takes advantage of Frankamp's greatest skill, which is his shooting. Oubre and Selden can get out in transition, as can Greene and White.
What about the big guys? Well, Perry plays better in a set half court offense, but from watching Alexander, I think he is comfortable in transition. Traylor is definitely a transition player. Not sure yet on Mickelson, which ultimately may be the determining factor. If Mickelson isn't comfortable in transition, KU may be a selective running team (i.e., run when the Chicago bigs are in with Mason and any two wings, play more half court with Perry, Mickelson, Frankamp and Greene on the floor).
As for zone defense, I think KU should show a zone as at least a change of pace look. I was advocating this last year with the size and length KU had at it's disposal, and I would advocate a similar look this year. I don't think Oubre will be the individual defender that Wiggins was, but I think he will be very solid. I still think a 3-2 zone could be very effective with the likely starting group (Graham, Selden, Oubre, Ellis, Alexander) because of their size and length.
I think a 2-3 would be a fun look if KU decided to go smaller (something like Mason, Frankamp, Selden, Traylor, Mickelson). That would be a good look to maybe change the look the opposing offense was getting for a handful of possessions.
I agree with @konkeyDong 100% that we need to embrace attacking matchup advantages. This has been one of my major criticisms of Coach Self in that he lets lesser talented teams hang around because he lets them play their regular rotation rather than basically telling them "you can't play your two worst rotation players today because I will destroy them whenever they are in the game." That's the single biggest reason UK beat Wichita State. Had Marshall been able to play his regular rotation, he may have been able to have enough gas in the tank for a win. But Wessel (12 mpg in the season, 3 vs. UK) and Coleby (13 mpg regular season, 7 vs. UK) were basically eliminated from the rotation because Cal went right after them. Self let a Stanford team without a true PG beat him in the NCAA rather than pressing them to death with a small lineup and making their zone defend Wiggins as a 4 man in the high post.
Exploiting matchups will be the key to success, over and above everything else. When we have a size advantage, we dominate. However, the high low doesn't give us the advantage if we are better on the perimeter. Look at the Northern Iowa loss. Or Stanford. Or Bradley. What's the common thread between those teams? All had a 7 footer on their roster that was pretty solid, which eliminated our typical interior advantage. But in each of those games, our guards were better (sometimes substantially so). But in sticking with the high low, we negated our own advantage by taking the ball away from our advantage and moving it to where they could play us more evenly.