I have fairly big hands and I've never had a problem with the size of the DualShock controller. I started using them when I was 6 or 7 (I think that is when they released) and can still use them perfectly now. Maybe I hold it weird (I don't use my fingertips for the shoulder buttons/triggers, I use my middle section of each finger)?
I wouldn't mind seeing a bigger version of the DS3 (to go along with the current size), just because so many people seem to complain about it, but I wouldn't like to see something too different in terms of shape/layout from what we have now. Whatever happens, keep the analog sticks at the same height as each other.