I've said it before, and I'll say it again.
I am from a large chapter, usually around 180-200 members after our deferred recruitment. I LOVE being from a large chapter, because there is always someone around to hang out with, there is always another ADPi in all of my classes, and it enables me to have lots of friends.
I know every girl in my sorority. Naturally, I have my close friends- but EVERY sorority has some girls that click better than others. And that's OK. If you want to know everyone, then put forth the effort to know everyone! I know all the girls because I make it a point each week to eat dinner or grab coffee with someone I don't know very well.
It's easy to blame a lack of closeness on chapter size. But unity comes from within...and my large chapter has it.