I agree. Upwork allows you to change the rate so why not anything else? You could edit your proposal in Elance. In my case, I forgot to answer a question about how long it would take (another missing feature). Sure, it takes a bit of getting used to especially if you used Elance before but it's disturbing that so many features are missing. Sorry to go off topic, but the one I dislike most is that you have to view the proposal in a separate window now.
The fact that there is a workaround to the problem is even more worrying. I.e, you CAN do it but we're not going to make it easy for you.