However, i3 is quite functional, and Stack supports overlapping when necessary. So there're some UX compatibility problems to think about.
I'd be interested to know what functionality do you really use on a regular basis. Especially, it would be interesting to know _why_ do you use it. E.g. not just "I want to split my screen in half and put W1 to the left, and W2 to the right" but "I want to see all my open windows the most comfortable way possible".
For example: generally you don't just want a chat window constantly visible, you also don't usually need it to take half of 30 inch screen. So with an ideal app you should say, that it does not require more than 10cm width and 6cm height, and WM will figure out the rest.