There is a part of me that feels badly that this thread has generated such heat and animosity. And then I see this
And I am just soaking it all in. Not in pleasure, but even in this open conflict, I am learning a lot. But if you don't mind me saying, I want to re-state something I think I stated earlier.
Different players play this game for different reasons. Maximus, you treat this as a farming game and you are striving for XP & loot. If that is your primary purpose, then perhaps you are doing the best you can at what you are doing - mission accomplished. Scrapz, I think you pride yourself on building a balanced monk (as do I) and it seems you enjoy the challenges it brings at different levels. If that is how you enjoy D3, then mission accomplished. Neither of you are more right, I don't think because in the end, we are attempting to play the game for our own personal enjoyment -- and the great thing is that we get to define what brings us joy in this game - that's what MP levels has done -- invite more flexibility and more ways to play the game and gives people like LordRaahl and Druin (to name two) to develop different builds and specs for entirely different purposes.
Personally, I line up more with Scrapz' philosophy. From the point that I decided to re-gear my monk about 13 plevels ago, I wanted to build a balanced monk (without dipping into RMAH). One of the things that I enjoy about the game is the thrill of the challenge that different levels bring. Nobody "farms" MP10 for xp/loot, but many may like to wade in there for the challenge and to stretch oneself. Being able to do MP10 comfortably allows for maximum flexibility in being able to play different levels for different purposes.
In a way, that's why I enjoy reading some of LordRaahl's posts and his guide -- he doesn't pretend to strive for maximum farming efficiency at all costs -- at least, I don't think that's his only goal nor is that where he seems to get his kicks from the game. That's probably why I thnk his posts are so often misunderstood (and gets called out for trolling)... because the basis from which he enjoys the game is different from what folks like maximus (no offence, just using you as an example to represent the many who have the same philosophy) strive for (which is maximum farming efficiency).
I think what I am trying to say is... let's respect the differences we each bring to the game. There is no one right way of playing -- we all get to define what's "right" for us. I suppose this is the ultimate in postmodern thinking. :)
Which brings me back to my original question. Embedded assumption in my question is precisely about how to move up in MP levels "comfortably" - which is what motivated my question about DPS:EHP ratio. This question bears no relevance in lower levels because the ratio can be all out of whack -- you can easily have 100K dps and EHP doesn't matter because you will kill monsters before they can get close to you. But the question does bear relevance for those (like me) who enjoy the challenges of higher levels, especially doing through "hard work" and constantly pushing the limits of my gear by working on skill (which costs nothing but time, brainpower and effort), on top of gearing (which costs a lot).
So I want to thank all of those who have answered this thread so far. The variety of perspectives has been amazing and it has helped me understand more about gearing for higher levels. Keep the discussion alive, but I hope that we can also keep it respectful as well. :)