Hi David,
Did you do the math? Are you sure angualr.js minified and gzipped is larger than the combination of backbone+jbone+lodash+hogan?
Is your site attracting lots of recurring visits? if so, the size argument is even more invalid, as angular gets cached on the first visit. If you use an CDN version there is a
large change it's already in the users cache. Compare that to the change your other combo is in their cache.
If size matters that much, you surely optimized all your images? took care of what loads above the fold? removed all obsolete CSS rules? Ok, I can add another few 100 questions here...
What I'm saying is, the size argument is a non-issue. If you think AngularJS is a right fit for your project, the size of it is the last thing you should be concerned about!
Regards
Sander