Increase the default size of page elements (font size, etc)
There's a lot to like with GTDNext, but I find that I don't care for how small everything is at 100%. If I zoom the page to 125%, I think this gives it a much more appealing interface. It would be nice to have the default be a larger size so users wouldn't have to though.
When I look at other sites, such as Todoist, Wunderlist, and Nachapp, their pages at 100% look very similar to what GTDNext is at 110% - 125%. It seems like a minor request but I think it makes it feel more user friendly and a little more "app" like.
In our January UI refresh we did slighty increase the size of elements. Hope that helps!