It's Horrible to Destiny New Upgrade Currency Model
In base Destiny, the last three upgrade sockets for legendary and exotic armo and weapons required legendary-quality upgrade materials called Ascendant Shards and Ascendant Energy, respectively. You could get these from dismantling other legendary or exotic gear, completing the daily heroic-mode story mission, doing public events and raiding. When you beat a raid boss and didn't get loot, you got ascendant materials instead.
As a result, upgrade materials became synonymous with disappointment for raiders; nobody is ever hoping not to get loot.
Bungie came up with a solution for this problem in The Dark Below: It decided to make players really happy to get upgrade materials instead of loot by making upgrade materials really, really scarce.
The new raid armor and the new legendary raid guns require new upgrade currencies called Radiant Shards and Radiant Energy, respectively, to upgrade. These only drop from the raid, which has has three bosses and two chests. If you get nothing but radiant materials from all the drops in a raid, you get a total of 10 to 12.
Each gun and piece of armor requires 21 radiant materials to upgrade. All the non-raid sources of legendary upgrade materials still drop Ascendant Energy, which is useless for upgrading raid gear.
Each character has four armor slots and the raid contains one of every type of gun, for a total of nine. To upgrade them all, you'll need 84 shards and 189 Radiant Energy. You'll never get that much, so you'll have to choose which guns to upgrade. And since the raid guns have the same damage output as the vendor guns, they're of limited use if they're not fully upgraded.
The shortage of materials the new currency creates will also cause other problems. The raid armor in Destiny has randomized stats. A chest piece can enhance your strength, your discipline, your intellect or some combination of two of those stats, and it can have a stat-point allocation as low as 120, or as high as 160.
In the Vault of Glass, since you had plenty of upgrade materials, you could upgrade the first raid chest piece you got to improve your Light level, and then replace it later on if you got one with more optimal stats. With the radiant upgrades now so scarce, if you spend your shards upgrading a pair of all-strength boots on your Warlock, you're going to be stuck with them.
Worse, because the game is so stingy with upgrades, the only way to reach level 32 by the launch of the new raid's hard mode in January is to do the raid on multiple characters of the same class, so you can collect extra upgrade materials without needing to upgrade multiple sets of armor.
In the Vault of Glass, people complained about the RNG causing them to never get certain loot drops. In Crota's End, people will be complaining that they can't upgrade their gear because they don't have enough upgrade materials. Never mind, you can upgrade lv32 through destiny power leveling on Destiny-Store.com.