I would like to see the following features in construct 2:
(because using incrementing a variable on every tick is messy)
.svg image support
(perhaps it will make it easier with responsive design if all sprites are vector based?)
editable code (text)
(using nested ifs aren't easy with event view).
be able to build and link libraries that is also written in C2.
(make your commonly used functions into a library that you can use inside C2.
JSON support(but i hear its planed).
load gfx and sound to localstorage and read from there.
to be able to run things in parallel
(maybe html5 worker threads can be used)