In World of Warcraft is it largely disliked to wear PvP gear in PvE...
...dungeons/instances? I'm relatively new and my char is lvl 70. After doing really not much PvP I was able to get a full set of rogue gear that outshines my (still) TBC gear. Do players get annoyed at those wearing a full PvP set in an instance - is it considered a pretty nooby thing to do? Or am I making a mountain out of a mole hill?
when I was level 80 before cata came out I had full set of pvp gear and I would run dungeons (5-player) and no one would really cared or atleast the people I got paired with so I would honestly say no
Not really. The only problem with PvP gear is its stats...its geared more for fighting against other players than it is instances. But a good set of PvP gear will be a good starting point for the instances so you can get some good PvE gear.
In a normal dungeon, it is actually better to have an epic PVP set than a bunch of greens and blues. However, in TBC heroics or raids, it is highly likely that a majority of your group will be annoyed.
Yea most people don't like it. I wouldn't do it for heroics, unless its old WOTLK content. And it will get you kicked out of a raid in less than a minute. But you are only level 70 so at this point in time it really don't matter. The dungeons you are doing right now are like day care so if anybody complains, tell them to f*%k off.