Let's see, doing a random dungeon awards 2 emblems of frost the first time you complete it each day. I'm sorry, but 14 emblems of frost won't buy you anything. All gear you can buy with those costs between 30-95 emblems. You will either need to do this a quite a bit longer, or get these though other means (such as doing the end game content with 9 or 24 of your friends).
Oh, I know about frost badges. My mage is in 3/5 T10. :) I didn't mean the "kill one guy seven times" figures exactly like that (although we could make a case for running one random heroic a day for 7 days giving you ~6 badges a run, enough for T9 head or shoulders). I meant the general design philosophy. I find it really jarring, personally, when quests require you to kill the same guy many times. The way they're going they might as well just make it "kill Hogger 10 thousand times and we'll give you all your Emblem of Triumph gear." The challenge level is the same.
The reason they have this once per day reward for doing the same dungeon, is to help keep a social atmosphere in the game (dungeons are set up to be done by 5 players).
Random dungeons aren't social. At best you get a 'hi' at the start of the dungeon and then it's silent for the rest of the run. Usually I'm gritting my teeth trying to tolerate the incompetence of the random fail DPSers I get.
Wow has set up the model of rewarding skill and dedication, having either will get you good gear, while having both will earn you slightly better gear.
This is true. Maybe it's stopping being the game for me quite so much. :/ I just wish they'd add a proper progression for 5-man groups, parallel to raids. They're sorta getting there with normal heroics, then ToC5, then ICC, but the gap in gear rewards between heroic ICC5s and heroic ICC25 is ridiculous. It's definitely harder tanking heroic Halls of Reflection than anything else I've yet done (up to Rot/Fester in ICC25).