Very few people are interested in push raiding and even fewer build for it. There are many reasons to choose ranger levels over a little extra sneak damage if you are looking for versatility vs. max dps. Max dps only really matters in push raiding where you run with mostly the same people and don't have to worry about anything but max dps.
Even for someone pugging R10s they are probably better off adding a little survivability and healing over max dps because groups don't really have any problem taking down bosses, but being able to throw better heals at the party (and esp a divine) can prevent deaths. When R10s are short-manned or pugged without the right roles versatility wins every time.
I don't disagree with your approach at all as it fits the purpose you are building for, but most people are building for something completely different and it might actually be to their detriment to sacrifice versatility for a little more dps.