Diablo'esque loot system + iLvl DOES NOT WORK, failure imminent
Simply put, this game will fail (if it hasn't already) by combining tiered gear with an RNG loot system. The entire premise of a diablo type loot system is that it may take you x hours to find that perfect piece, but when you find it, it will be good for your build for the long term, usually. However, when you combine that with higher tiers of gear it creates a treadmill where the carrot on the stick in front of you isn't even visible anymore.
Imagine this, you've been farming hornet or whatever for that perfect piece, or just an upgrade, and it drops. You're ecstatic, you finally got an upgrade after dozens and dozens of runs. Low and behold, the next tier of iLvl is around the corner, and that 183 gun that's awesome right now, is going to be outclassed by the 240 gun regardless of talents.
Aside from all the bugs, glitches, hacking, lack of content that needs to be addressed, I feel that this is something that needs a serious overhaul as well. The way the system is set up now is not sustainable and people that stay through all of the other glaring problems with this game will eventually be worn down by this.
Just my 2 cents. Again, this is all just an opinion, feel free to post your thoughts or why you think the system is fine or what can be done to improve it.
TLDR; Copy Diablo's loot system or use a traditional MMO type loot system. Combining the two is a mistake.