I always feel torn about this kind of debate. Part of me; sensible me, believes Herge's wishes have to be respected, but then there's the child-like fan in me that wants some fantastic new adventures written. It's a testament to Herge that despite being over 70 years old, and the series effectively (and abruptly) ending 20 years ago that people would love this to happen.
I like the 'parallel universe' idea applied to Spirou; then Herges 'world' would stay untouched, and different writers and artists could be comissioned to offer their takes on Tintin. The stories might be good, they might be bad, but at least they'd be out there.
Moulinsart MUST demand quality, of course. If Moulinsart decided to grant that privilege, they won't let just anyone create a Tintin story. And they would supervise.
True.The success of bringing Doctor Who back to life was to give the franchise to those who knew what they were doing. Russel T Davis was well respected as a writer before, but more than that; he was also a fan of the original series. I'm sure that there are some great writers and artists out there who are Tintin fans who would do a darn fine job.
I doubt it'd happen in a million years, but a girl can dream.