I'm in the same boat, rarely re-sizing windows, and I'd do the same thing, but I use Tmux and terminal Vim and using the mouse there just doesn't work in my terminal emulator. (I use st[0] on Linux. It probably would work in iTerm on Mac, but I haven't tried.) It also may not work due to Tmux being configured with mouse support.

[0] http://st.suckless.org/