If the anime has been going this long and is still successful, it would be a risk to change the animation to CGI, and likely a risk that wouldn't have a whole lot of gain even if it was successful. So the odds of it happening in the foreseeable future seem pretty slim.
As for if it would work? Maybe later on down the line, when CGI can be done to a quality-level at a lower budget. But even then, it'd still look worse than higher budget fare, and as such, the CGI might be more distracting than anything. And that (to me) is at a best case scenario, so I think the anime should stick with the 2D animation. It works, and there are no significant problems with it, after all.