There are some schools that dont require (but prefer) a baclelors degree... so if you appy without one.. and dont get in ... then later on re-apply after your done your degree - does it decrease your chances or look bad (b/c your re-applying) ?
IU seemed not to care at all about whether or not I had a Bachelor's degree. So if you don't get in the first time around, not much would change the second time around. You'd have to answer the same reapplicant questions of "What have you done since last year?" but the degree wouldn't make much of a difference.
At least that's the feeling I got from them about it.