I think looking at games like WoW, DnD, etc., is probably not a good comparison. While they are all RNG, those are all very well-balanced games and unfortunately this game is not. I know through all the WoW raids I finished with my guild, I had seen all the rarist of gear drop multiple times.
I think the dev team is definitely thinking through Mods because their latest survey was very mod-centric. I don't know how much more information they need at this point. Generally speaking the secondary stats are definitely better than what you find on the set bonuses. The potential is there to increase speed by approx 53% (mean speed = ~121.8) from secondaries, meanwhile the set bonus is only 10%. I've seen offense mods with 99 offense and other shapes that are close, so I'm speculating that the offense bonus from non-offense mods can be better too. Yesterday I picked-up a Mod with almost 4% Tenacity on it, so one piece is almost as good as the 2-set bonus. Either way, I think it would be more sensible to have something like a speed 2-set bonus to give like +25% speed and the 4-set to give the 50% and then setup the secondaries to be closer to 5% and 10%. Something like that would at least create some semblance of balance in how the mods are setup. Otherwise, why pursue specific sets?
