I sympathize. It's my one beef. For me, it's the menu and Synaptic. Neither will enlarge no matter what I've done. Once I installed everything I use regularly and set up docks, I never look at either much anymore, so I'm less troubled. I haven't been annoyed with the sign-on, but I know it's tiny. It would be nice if the issue were uniformly resolved, I agree.
Linux Mint 17.1 Cinnamon
Linux Mint 17.1 Xfce