The problem with a "2D" text is that you think in your head that there's all these amazing possibilities that you're creating, when in fact you're taking on vastly more constraints. For a sort of simple analog to that, observe the number and nature of the Platonic Solids in various dimensions, and observe that despite the fact that the increasing number of dimensions might strike you as making it obvious that higher dimensions should have more and more Platonic solids, the number of constraints increases faster than the degrees of freedom do, and instead you get the same degenerate set of solids in 5+ dimensions, forever.

Visual programming, another ever-recurring supposed replacement for text that is just obviously so much better and programmers are just stupid for sticking to plain and boring text, has a similar problem, where in return for whatever visual organization it makes possible (but does not force, since you can still make stupid visual programs) it is countered by the annoyance of suddenly having so many more constraints on the program, like, having to worry about layout, and how the lines cross each other, and whether some part of the program is literally overlapping another, and how all these concerns tend to grow as O(n^2) on the number of elements if not confined somehow. This one has led to some modest success in certain limited environments, but as a replacement for textual programming it fundamentally flounders on the fact that its additional constraints creates problems significantly faster than it can solve problems.