Depends what you want I guess.
In general, 24p on consumer cams blows. If you want the filmic look, do it in post.
You are gonna have to decide which you want to give up, image quality or fluidity.
Televised sporting events are works or art and dont think you will be able to acheive that with just one camera. Most big time events now are shot in HD at 60p. I wish I could. They also have special cameras dedicated to slow-motion shots only.
I would say shoot at 60i, then deinterlace in post for your slo-mo stuff.
Also, cineframe on the sony cameras is horrid. I shoot an Sony Z1(the FX1's big brother). If you need any help, drop me a line. I'm getting pretty good with it.
and PLEASE....dont add a damaged film effect on your shots. everyone is sick of it. its a fad. good, clean, in focus video will never go out of style.