I think a lot of the frustration comes from the fact that you and others are not understanding the point of view of Civ players who like to play
peacefully, and for whom an "overall game strategy that includes settling, building, diplo, researching etc., not just military strategy" is absolutely key to enjoyment of the game.
It simply isn't the case that my complaint (and, I suspect, the complaint of others) is that war is the "easiest" strategy to complete. It isn't. Cultural is pretty easy actually, I don't know if you've tried it? I see your comment on it, but I don't bother building much military ... what for?

"Diplomacy", frankly, is a breeze (I confess I haven't tried Deity on this but ... how hard can it be, really?). The problem is not ease, or even viability, for me. The problem is that when I play for - and win - cultural or "diplomatic" or science victories, even on higher difficulty levels, there is so little to do for most of the time that the game has no interest. There is no real complexity to it, no breadth of options and little depth. Once I've made up my mind what I'm going to do, and built the few units I require to stave off the inevitable and poorly organised AI assaults (5 units generally suffices - in fact, I suspect a couple would do the trick but I always feel I
ought to have more somehow

), it's largely a question of clicking end-turn over and over again and then waiting forever for my building of choice to complete and, each turn, for the game to grind through whatever it is it's doing and present me with my next opportunity to click end turn. Generally, inbetween turns, I pop off and do a small household task or make a cuppa - and this may sound facetious, but I am telling you that sometimes the turn
still hasn't ended when I get back 
Aarggh. If I were not a Time victory veteran from IV (which makes me a sad git, yes I know

), I really wouldn't have the patience for all this!
I think you will find that's what people mean when they are talking about the lack of options and depth - it's not whether or not there are options per se, it's that, if you play peacefully, there's
almost nothing to do from the mid-game on other than that endless, tedious manipulation of research agreements and occasionally choosing a new building. As a friend of mine said "I intend to go for a peaceful cultural win, but I end up declaring war just to relieve the tedium ... "
Now, how can that be right? It's a real shame, honestly, given how interesting previous iterations of Civ could be for peaceful players.
I think that was what the poster was trying to say (and apologies to him if I've got him wrong). But at the very least, it's
definitely what I'm trying to say. And I think that's why I really didn't regard the post you have so helpfully repeated as a response
PS I've just re-read your post, which to me seemed to be an explanation of why Civ V is a war game, but apologies if I have misunderstood. What I will take issue with, however, is your suggestion that "If you miss 2/4 cultural wonders, you may as well quit trying to win a cultural victory". I find this baffling, and it was this statement that made me wonder whether you had actually played many - or any? - peaceful victories. The wonders in V are really fairly poor and I don't think I usually build more than one or two (except to relieve the boredom!) I certainly wouldn't regard wonders as essential for a cultural victory - they make it easier of course but essential? No.