Many of my friends are pursuing Biology degrees but are done with their prereqs this year so they applied even though they do not have degrees and will not have the degree by this summer. If they get into pharm school this year they will just drop the bachelors degree pursuit and head to pharm school. If they do not get in they will continue after the Biology degree and apply next year with a BS in Biology.
I would make your prereqs your first priority and finish them first but it doesn't hurt to take classes toward a bachelors as well, it is like an insurance policy, if you do not get in the year you applied without it, the next year when you apply your application will be more competitive with a bachelors. I ope that made sense...
Personally I was pursuing a Biology BS and was going to finish it this summer but when I found out I got into Pharmacy school a few months ago, I just switched my major to General Science because I can finish that degree this term with only 2 classes!
Also like you mentioned, schools are becoming more and more competitive, having a BS does give you a stronger application. You could say it adds "maturity" to your application. It lets the school know you are capable of pursuing and completing something and that maybe you have payed your dues. A degree is not needed though, it is just something else to strengthen your application.
Sorry to keep babbling but I would also like to say, It is GOOD to pursue a degree because the truth of the matter is that only a small percent of those who apply to Pharmacy School actually gain admission, so having a Bachelors degree gives you a college education to fall back on if you are unable to receive admittance to pharmacy program and choose a different career path.
