I doubt its because of complaints about the number of collections. They're prolly having production/distribution issues. If the problem was customer complaints, they'd be more likely to have current collections launch as planned then slow down next year, as one week won't make much of an impact if people are getting collection fatigue. Production, marketing, budgeting, distribution and sales projection for collections get planned months in advance and at this point, they'd lose money if they pushed back for a non-logistics related reason, esp in the 4th qtr of the year.
On the issue of too many collections, I think we should bear in mind that we Macaholics are NOT typical MAC customers. Most people don't a) keep track of every collection, b) feel the need to purchase any or all of it and c) don't have enough of a MAC collection to be bored by or already have dupes for new releases. That's the reason Shroom, Satin Taupe and O are best sellers.
The avg customer just goes by the counter to see what's new when she's on her way to the shoes/clothing/housewares dept in Macy's and it makes good marketing sense for MAC to always have a new look/display to entice her. The eye-catching theme day makeup and sometimes risque posters of the collections are not only there to entertain us loyal customers, but bring traffic to the counter/store. How many of us feel drawn to the Clinique/Lancome/Clarins counter because it looks interesting and has an eyecatching display or poster? Didn't think so. Yeah, it might be annoying, but MAC has found a good business strategy and they are probably going to stick with it. Have you noticed that everyone is doing LE now - look at Bath and Body Works. Every couple weeks they have a new LE scent or collection. Same with higher-end perfume companies and their LE/flanker scents - Calvin Klein, Burberry, Escada, Michael Kors, Dior etc. Companies are jumping on the LE bandwagon like crazy and it will probably get worse before it gets better.
OK, I'm done now. Sorry for the epistle. I don't work for MAC or anything, but I really admire their business srategies.