I think Michelle's range is stuck in a rut, unfortunately. The prints change very little, the fabrics change very little, and the designs don't seem to change at all.
You can't even say that she's designing for and dressing herself, as she rarely appears head-to-toe in her own fashion. Normally she's got a top with a jacket or cardi with jeans.
I'm sure she has some very loyal customers who are very happy with what Michelle sells, and it does sound as if their customer service is good, but I think she needs to be a little more adventurous.
Of course, this could be yet another occasion where the QVC straitjacket (give us your best sellers, we're not interested in something that's not a sure thing) is what is actually limiting her from evolving her range.
I also have to say, that while many think the fashions seem to suit Tiffany more than the other models, to my eyes, the MH fashions make Tiffany look every bit of her age and maybe a bit older.