I do think its overly complicated. It is going to be a major pain to clean out all of those filter pads.
I would do EITHER filter socks OR filter pads at the beginning of the sump, but not both, because that's kind of redundant and not needed. Having a set of pads after the plant area is good to keep any dead plant debris out of the biomedia chamber. If you're going to use bioballs (or pot scrubbies), then I don't think you need to add the ceramic media underneath, but I guess you can if you want.
What head height are you pumping against? I use 2x quiet one 4000's, pumping up about 4.5 feet, and I'm getting almost 1,500gph, so I'd think 2x 6000's would be more than 1,600gph. You just want to make sure you're not pumping more than your overflow can handle.