Have you actually tested that on beta? The Str:Stam ratio seems to be pretty even on items. Artifact increases stamina by 25.5% when maxed. On the other hand, Dragon Skin increases ignore pain absorption by 6% at all times and Dragon Scales can proc for an additional +60%.
When it comes to secondary stats, there's actually not as much of a difference as you'd expect. Blizzard really scaled up secondary stats at the beginning of the expansion (at the cost of secondary stats no longer increasing as much with ilevel). If you wanted to stack mastery for soloing, you could easily get >10k in pre-raid gear which is +43% for 55% total mastery. That's pretty comparable to what you have in current endgame gear when stacking mastery (and possibly even higher).
The only real loss when it comes to your absorption per damage taken (or absorbed) ratio is your set bonuses.
By the way, this isn't only based on theory but I'm also seeing these numbers when actually comparing live and beta characters. With not very optimized gear, just the tooltip value of ignore pain (which is missing Never Surrender and Dragon Scales) is still ~36% of total HP.