I've been testing a warrior for 2 days.
Here is my observation for rage generation:
a standard formula :
Character : 60 lvl "Naxx" warrior ( 440+ def)
test №1
1) NPC: Highlord Taelan Fordring 63 Elite (Hearthglen)
hits 480 - 520 --> 13-14 rage point (.....?)
crushing blow ~ 750 --> 16 rage point (.....?)
2) NPC: Molten giant 61-62 Elite (Molten Core)
hits 450-600 --> 12-14 rage (......?)
test №2
1) NPCs: 54-56 Elite mobs (around Hearthglen)
hits 200-350 --> 3-4 rage point (according to the formula, works as intended)
2) NPCs: 58-60 lvl none-elite mobs (throughout the world)
hits 50-130 ---> 1-2 rage point (sometimes their hits do not generate any rage at all, but still works as intended)
Conclusion:
Rage generation works as intended when a warrior is being hit by any NPC in open world, if NPC's lvl is 60 or below.
Being hit by 61+ Elite NPC generates different amount of rage and I can't find any explanation.
On the bright side, unlike Kronos server, here rage is being generated when normal melee attacks were parried, dodged, and blocked by a warrior, what, in fact, is the main reason why warriors have bad times on Kronos.