You've identified the cases where you don't want sleep to kick in (browsing). What are the cases where you do want it to sleep? When it's on the home screen? When some other app is active?
Personally I don't return to the home screen from the browser (or whatever) before putting the unit into sleep - I just tap the power button when I'm done. Assuming you leave the browser up but you've now got something saying "never sleep if I'm using the browser" then the unit would never sleep so the 2 minute battery-saving setting would never kick in. Alternatively if you actually do religiously return to the home screen when you finish browsing so that the unit can sleep after timing out, why not turn off auto-sleep and just touch the power button instead?
I can't imagine there are any articles that take more than 2 minutes to read without scrolling so the only case I can see where this would make any real sense would be watching an embedded video since YouTube will keep the screen alive beyond the 2 minute timeout. I guess the only workaround I can think of for that would be to just touch the screen occasionally.