I like the hire, at this point in time. If this were a Mike Riley situation....hiring an older coach to transition a successful program over the hump, I'd hate it. I don't for a minute think Les Miles' rather archaic style fits that kind of job. This is a builder's job, almost from the ground floor.
For KU, it's almost easier to build that roster from scratch. They only had 28 scholarship players in the first spring of Beaty's tenure, and just finally hit 70 this fall. An FCS school has 63, for comparison. It's even worse than that because over half of Beaty's players were transfers. Their class sizes are totally screwed up and they lose a huge chunk of what little talent they have, to be replaced by the 1 commit they currently have.
What KU needs in the immediate future is someone that can recruit and sell the program. They need significant facility and stadium upgrades to be even remotely competitive. That means someone has to pay for it. That's fans in the stands and boosters. A big name hire like Miles that knows his way around major college football is ideal for that job. They got him relatively cheap, too, at about 2.8 mil a year.
When he's ready to retire in a few years and has elevated the program, then it's ready for a coach that wants to run a specific system that can then take them to that next level. Right now, KU mostly needs someone to make KU football interesting, and few are more interesting than the Mad Hatter.