Thing is, you have to consider the business model. For new players, all the "old" low level content IS new. It's the established players that, a) have "worn out" all the existing content b) generally have high level toons c) have a documented history of spending money on the game. So, it makes sense to cater to the player base that's paying the bills.
That said, I'd like to see a new mid-level quest pack. Everyone seems to agree that Restless Isles and Threnal suck rocks, which means that the offerings are a little thin in that 7-11 range. There's stuff there, but you're somewhat locked in to which packs you run between Delera and The Desert. When you're able at level 1 to pretty well map out which packs you'll run all the way to level 20 with only a couple "this or that" branches (and it's worse for first lifers since they level past some packs before getting to run them), I think you need a little more content.
I wouldn't say that the 7-11 range really needs a lot of content. From 7 up, we have Sentinels, Sorrowdusk (which runs the whole range of levels), Delera's, Necro II, Vault of Night, Tempest Spine, Xorian Cipher, Red Fens, Desert, Ataraxia, The Pit, Necro III, and probably a whole score of stuff that I'm forgetting. This is leaving out Threnal and Restless Isles, which both suck.
Compare this to 16-18. We have Necro IV Elites, Vale of Twilight, Harbringer of Madness, Reign of Madness, and Inspired Quarters I. IQII, Shavarath, and House C Manufactury are all 19-20 really.
So the quests are falling in where they need to to fill out the content in the level ranges. Really the first several updates that came in since I started were catering to the incoming low levels. From Chronoscope raid at 6, to Carnival (5), Sentinels (7), Lordsmarch (11-13), etc... That's not to say that they don't need to release new content at the low levels; they should just for those who TR if nothing else. But for after IQ2 was released in U2 or 3, there wasn't any high level stuff until Reign of Madness and House C.