It's pretty debatable, whether or not any testing/validation occurs, more importantly, the depth of the playtest and its scope determine what issues are caught/fixed. Considering the age/life of the game, the relationship to the publisher, it's more than likely that the once huge team of QA Testers is no more than a skeleton crew with pressing deadlines. Dev/Release cycles are not exactly as most assume they are: a project isnt simply developed when advertised. In most cases, it leaves preproduction and enters the test phase during a period when a predecessor is still in market. In this case, Seasonal content is not a focusing point for Bungie, it's a matter of iteration. What you consider a season is no more than a content patch. Patches are not a high priority. Reason being is they've been tested over and over and balancing is not as simple as base damage. You forget about enemy ranks, associated resistances, etc. Now compound that with classifying enemy Gaurdians and classs/mods, etc. Bungie is doing exactly what is necessary to keep D2 relevant; after all, conversation, no matter how controversial about a product still brings attention. Whether or not a weapon can be "nerfed" or "buffed" isnt always as simple as a few lines of code. Consider each weapon per as a module tied into a larger system that not only calculates perk appropriation, slot placement, but the actual methods/expressions/calls needed to trigger the perk effectively. A Library/Table system to not only define and handle the aforementioned but also to globally manage the number of perks whether exotic or otherwise, a system to validate the target, and calculate weapon performance based on perks and the games world rules... Theres a lot of interplay that happens with a game of this scale and a weapon library meant to be expansive as this game's. Not defending the project by any means, just stating some facts. I worked in QA on Triple A titles so I know firsthand how chaotic it can be.