I'm not opposed to a "complicated" offense in theory - but that doesn't mean every play needs to be complicated - nor does it mean that an OC can't consider the talent, skills and capabilities of the weapons at his disposal.
Three questions for you:
1. Do you consider having a WR run a deep sideline route "complicated"?
2. Do you think there's room in an offensive playbook to run such a play at least a few times a game?
3. Do you think it would have helped the offense to have a deep threat WR on the opposite side of Moss for defenses to contend with?
My answers to those questions are No, Yes, and Yes.
I'm not sure if McDaniels feels the same way.
I'm not asking him to "dumb down" the entire offense - just to use a simple, standard play that many teams use. In Stallworth's case we had a WR who most DC's respected as a deep threat - at least until McDaniels stopped using him as such.
Next season we're probably looking at Jackson in that role - and unfortunately he's not one who DC's respect - and its in the team's interest to try to establish him as at least a moderate deep threat. And yes, that will probably mean some "dumb" simple, deep, sideline routes.
And that's a bad thing to do, why?
That's not "dumbing down" the offense IMO. But indeed, sometimes an OC does have to make concessions, just like Weis did in simplifying the playcalling when Brady first came in for an injured Bledsoe. Was that a bad thing in 2001? Not judging by the outcome.