Yes, even basic things like getting modifiers, scroll a field and more-than-7bit-ascii keyboard support are still missing.
So, currently one needs some javascript code to get a medium advanced stack running in HTML5. (I wrote some free helpers for that.)
On the other hand you have the option to take the best of both worlds. That's not a limited solution, that's *far more* than the old fashioned lc-server or cgi solutions etc.
For example image processing by using the GPU via javascript together with the GUI of LC (which is more powerful and easier to use than some very large JS libraries) has become a very powerful tool.
Look at some of my newer HTML5 examples here
http://hyperhh.de/html5/large-index.html
and you will see at least a few things you haven't seen done by other LC tools or pure javascript/HTML5.
You ask for plans to go further in HTML5?
I fervently hope so.
And, if you can afford it, please support it by bying a HTML5 license. That's the way to realize wishes.