I think the majority of time they are filling in, because they cannot think of anything intelligent and useful to say about the products as they've not done the homework.
For clothing, I would far rather they gave the information which we cannot glean by looking at the garment on the model:
1) measurements
2) fit - is it snug to the arms/legs, and if so what are the diameter measurements for these
3) fabric composition
4) does it need a camisole/slip/shapewear to look its best? Yes, this needs a bit of unaccustomed honesty, but please try!
5) washing instructions - can we wash it, at what temperature?
Rather than hearing someone drivel on about wearing it with a boot/shoe/jean etc (whatever plurals they can singularise to sound extra stupid)... here's an idea - why don't the stylists show it in different ways it can be worn? Last time I looked, TV was a visual medium, and the rule is to show, not tell, wherever possible.
For fragrance I'm afraid they need to bite the bullet, talk about fragrance families and try the "if you like [insert well-known fragrance], this is in the same family so you might like it", even if shock-horror, they don't sell the one it's supposed to be similar to. They might have to cite more than one non-QVC well-known fragrance to be more helpful.
I know whenever I go and ask for assistance at a fragrance counter, the first thing they ask is what kind of fragrance do you like so they can point out ones which might also be appealing. As QVC is essentially a retailer, they should try to use some of the best of the sales training given to staff at stores... not all of it is passé for selly telly!
With the beauty products, apart from the fact that they need to be showing them on air less, they could do with using models with different skin types for different ranges, and get them to use them for a period of time... I dare say that means they need different models, and more of them. What is the point of demonstrating skincare for dry skins on someone with an oily skin, or vice versa? And when the same models show up on umpteen different beauty shows swearing X has made such a difference, we know fine well they are saying it because that's what they're paid to do.
In real life sales, rather than the antiquated world of QVC, there is a clear direction towards selling the experience of buying from the particular vendor. I can't say I'll be leaping to the phones when I get an offhand "phone Liverpool for details", and wait for ever (or until the product is limited stock) to hear relevant information.
Rant over.