Hmmm yes I did wonder if the new items would be worth getting it for, my gear is pretty out-dated now, most of it probably needs to visit the trash barrel! Are the new dungeons all for high level characters?
Id recommend that if you want to update your suit, start by getting one semi-custom made via Imbuing/Tailoring.... this suit does not have to be max spec, just some nice LRC,LMC, MR,MI as basics, which in time will open you the option to hunt for legendaries in harder dungeons, and then slowly start adding legendaries to the suit.
Although just for saying legendary a piece doesn't mean its going to be the best piece, as you may find that some Greater/Mayor artifacts may fit better into the suit. Its matter now of pick & mix till you get the mods you want on your suit and feel comfortable playing it.
Going with a good guild or group of players, should allow you to be able to hunt without being a high-level char, also, what do you mean by high level? Skill wise?
As for say, if you were 7 x GM, you can still hunt this places, just your spells or damage output wont be as high as a specialised character for say, Mysticweave mage, which can WoD at 120 SPWeave.
Id like to add also, depending what shard you play on, you might find legendaries for cheap for grabs if you got some gold saved up which should help to aim for a higher end suit.