I think that your #1 is pretty "you specific". In other words, what percentage of gmail users need to "compose multiple emails at a time"? I'd guess it's right

I think that your #1 is pretty "you specific". In other words, what percentage of gmail users need to "compose multiple emails at a time"? I'd guess it's right around 0.0000000001% (which represents you specifically hehe). I'm joking around a bit but seriously - that's not a "feature" that most people need, is it? Personally, I like changing my flow to work on an email. Chat is different - I want to do that inline with other things. Email though requires a different focus level (or it should) thus having a dedicated page works better for me.