WebGL is pretty powerful and some things could benefit from allowing an object to be drawn, even as code. I feel Construct is not using as much of the awesomeness that is WebGL.
Drawing a 1 pixel line is a scenario, for sleek types of guis. This typically requires an image which construct tends to hide the 1 pixel line as you can notice when resizing a window with one in it. The line seems to hide on it's own depending on pixel size as it squishes the image down.
A nice feature would be able to draw lines or other shapes using Construct, even through just code by settings the vertices manually be be great. This would allow pixel perfect lines to be drawn for situations like HUDs, and possibly other scenarios.
This is just an idea and I know would help me out some.