If you watch Mitch's interview with Dorsey, he talks about taking the BPA and how it's his philosiphy. He talks about how they kept taking WRs like Jordy Nelson and Randall Cobb in Green Bay for example when they didn't need them.
I might get killed for this but, Geno probably isn't the best player available at #1 per Dorsey's terms imo. It is probably Luke Joeckel, Star Lotulelei, or Jarvis Jones. Those guys are probably the best prospects in the draft.
Geno might be the best QB prospect in the draft but, he's probably not going to be the best player on the Chiefs board. For example, Per Dorsey's draft strategy, I believe we would even take Jarvis Jones if he was the best player on the board. Even though we already have Houston and Hali.
I'm sure many won't like it but, he basically said it himself. He doesn't draft for need.