For me it wouldn't be an adequate replacement - I like to work on my code offline and run development servers of my computer, but it's easy to imagine a simple setup where I log on to a remote machine through the tablet and work there.
I'm pretty sure we are agreeing here. If they don't do everything a computer does, they are not a replacement for a computer. If they do everything you do on your computer then they are a replacement for your computer.
For me it wouldn't be an adequate replacement - I like to work on my code offline and run development servers of my computer, but it's easy to imagine a simple setup where I log on to a remote machine through the tablet and work there.