If you look, I think you'll find a version of this discussion on every fly-fishing website, with many of the same opinions being expressed, ad infinitum. What's more, versions of this debate were raging long before any of us were born. More than simplicity vs. complexity, or imitation vs. presentation, or a few flies vs. many, I think it is the tendency to assume that there is some universally right or wrong approach that leads to confusion, especially for newcomers looking for help. And rather than the debate providing clarity or answers, it often contributes to the notion that fly fishing is baffling and incomprehensible.
Try this: Consider that our opinions and approaches are shaped not only by personal preferences (the approaches we enjoy), but also by the waters we fish and the ways we find success in those waters. From this perspective, it's usually possible to make sense of all the various approaches and to apply those lessons to other similar waters.
For example, an angler who fishes mostly small, relatively impoverished (fertility/food) streams for wild trout, soon discovers that fly choice and imitation are minor or insignificant considerations, and that approach and presentation are everything. If that angler can present a fly to the fish without scaring the bejesus out of them, he (or she) stands a good chance of success. (This is providing that the angler also has the sense not to constantly hammer the same locations with the same flies day after day. Even these hungry and eager fish can learn to shy away from flies under constant pressure. I've seen that happen time and again when "secret" little waters were suddenly exposed to increased pressure through publicity.)
Along the same lines, an angler who fishes mostly for stocked fish in a put-and-take situation can catch fish with most any fly and can even succeed without much skill from an approach and presentation standpoint. That is, until later in the season, when the few surviving fish finally start to wise up a bit.
In contrast, an angler whose home waters are larger or richer, and have abundant or diverse hatches that capture the fish's attention on a regular basis learns that there is some point to trying to imitate or suggest those hatches on at least some basic level. Of course, there are some anglers who can find success even on these waters by ignoring the hatches and either fishing at other times or by locating fish that are not so preoccupied by the abundance of a particular food. Unless these same waters are also subject to lots of fly-fishing pressure, even the "hatch-matcher" only rarely has the need to go beyond basic or classic suggestions of those hatches.
At the far end of this spectrum is the angler who fishes rich waters containing fussy trout that are subjected to almost constant pressure from highly skilled fly fishers. That angler often finds a need for continuous experimentation and adjustment in order to have regular success. Sometimes this takes the form of an extreme focus on imitation or presentation, or both. At other times, anglers can find at least temporary success by ignoring all the "rules" about both aspects in an effort to find flies or methods of presentation that the fish have not yet learned to resist.
Of course, there are many possibilities presented by any given stream or situation, and on a given day, any one (or none) of these approaches might yield success. But, through the course of the season, it is usually the character of the water and the way it shapes the lives of the fish and their reactions that determines the overall approach.
I'd encourage every fly fisher to read the beginning three pages of the chapter "The Dry Fly, Upstream and Down" in A.J. McClane's classic book,
The Practical Fly Fisherman. In it, he describes the very different approaches of three very successful fly fishers. He says:
The schools of thought that fall between the extremes of these three men are infinite, and taken at their face value it would seem that somebody has to be wrong. If you stop to analyze each, however, without getting involved in what the trout sees or thinks, vagrant facts begin to make sense.
Take the time to consider what McClane says in those pages with an open mind, and you can't help but realize that each of these fly fishers had become so skilled at his personal approach that he could catch fish just about anywhere. And that may be the ultimate answer to reconciling all of the different opinions and approaches. As William Blake famously said, "If a fool would persist in his folly, he would become wise."
Best,
Gonzo