Guys everyone has their preference and tim I honestly think you made the right choice.
If you already know WP and it's faster for you to solve the issue instead of spending hours maybe weeks trying to learn MODX then you have clearly made the right choice.
I know we all love MODX but think if we were in tims situation would you waste your time trying to figure out how to fix something in WP and spend countless hours or would you rather scrap it and convert it to MODX?
Tim was looking for a an easy solution the problem is we have no idea how the developer setup his site and I think this is one of the things that is both good and bad about MODX because there's no standard on how things are done and each developer does things differently.
Tim WP is the most popular there's no doubt about it but popular does not mean it's better.
If you decide to one day try to learn MODX we'll be here to help, because we can all get along