I really don't think the platform is the problem, here. And I think it's less a problem based on code than it is a problem rooted in some of the basic ideas of linguistics, since someone was talking about this above. Bear with me here.
As someone (I forget who you are now, sorry, and I don't wanna dig, but total kudos to you) said: with any system, you're going to have to learn how to talk to the system. You're going to have to learn how it identifies objects, how it identifies verbs, how to give it new definitions for things, etc.
And that's what we're running into here. Graphical things take some of that and make it unncessary, but also cost some things when it comes to robustness. Graphical systems are the equivalent of me just pointing at a thing and hoping you understand, versus me telling you what it is I want you to do with it, what it is, how to do it, etc.
This hobby isn't about shiny things. It's about communication. It's about learning forms of exchanging information and interacting with a non-physical environment in a medium in which you only have a voice. Graphical systems are generally the functional equivalent of beating on things and grunting, as far as input-output exchange goes. Very basic and simple, even if they are pretty flashy.
More robust GUI's give you something like... photoshop. And everyone bitches what a nightmare that is to learn, too, so I really don't think that the problems that we're experiencing with the hobby are going to be solved by moving to shinier, more graphical interfaces, because these two things aren't the same and cannot emulate one another effectively.
If we want to simplify the system, we can talk about various ways to redefine the code we use, but it's still going to be the effective equivalent of learning a language. Right now we're using one way, but there are other ways that information can be exchanged, as multilingual people can tell you. Maybe a system of flags that act as something like particles in japanese, or something like how Bash does it, but either way the system is still going to be complex because of the sheer amount of information you're going to have to learn to convey across the system in a brand new way.
I think that just changing clients without addressing what I feel is the real root of the problem is going to be problematic. As much as studies say that people's literacy is going down, but they're reading less, people consume more information on a daily basis now than they did decades ago thanks to the tools we have. It doesn't matter if they aren't reading a book a month if they're reading a hundred web articles a day. The capacity for learning new things is higher than ever.
So let's try and find a way of communicating that streamlines things in a way that people find intuitive, rather than trying to reduce the robustness of what's possible to use. That's what Call of Duty is for.