Re: Whats the deal with stick size?
It's about using the right tool for the job. Like, you wouldn't want to use those clubs for a gentle jazz gig in a little jazz club, and you wouldn't want to use sticks that are like toothpicks for a hard rock gig in a large venue or even outside.
Although, if you're in just one band and your gigs are pretty consistent, then you can usually stay with just one size. However, if that band has a large variety from gentle quiet soft ballads and stuff that's like soft jazz to really heavy hitting rock and roll, then you'd need to have at least 2-3 different stick sizes from which to choose. You might even want to have the choice between nylon and wood tip as well as different tip shapes and sizes, different tapers, etc.
I mean, sticks affect the sound too as well as your playing due to their feel, so it's not really good to force one stick size to work for everything that you play unless that stick size is working very well for everything that you play (which would mean that you don't have a very wide variety of things that you play which is perfectly valid). Of course, it's important to find sticks that work well with you in general as opposed to just dealing with sticks that don't work so well with you.
I'm fortunate in that I can keep it simple. I always use Vic Firth 5ANs because they work very well for me for everything that I play. :) I'm not a professional who is in demand and who is fluent in many different styles of music, and the band I'm in doesn't play anything that ever gives me the need to change my stick, so I'm lucky because I like consistency.