I thought it would be interesting to look at Wii U's launch and compare it with the Wii launch, with regard to actual sales. All data in this first post is coming from VGChartz
First things first - US system sales and total game sales in first week. Now, it's worth noting that, because both launched on Sundays, a full week is represented in both cases - no asymmetry in terms of time for selling.
Wii: 463,466 units sold, 1,372,834 games sold in total, tie ratio of 2.96 - note that this includes Wii Sports.
Wii U: 411,850 units sold, 1,139,618 games sold in total, tie ratio of 2.77 - note that this includes Nintendo Land.
Other than the 50,000 fewer units sold, it's fairly consistent between the two. If we assume that nobody bought the Basic Pack and then Nintendo Land, then the 112,119 Basic Packs, if they'd had Nintendo Land, would have boosted total games to 1,251,737, and the tie ratio to 3.04. So the difference in tie ratio can be attributed to Nintendo Land not being a pack-in with all units.
Now, on to a few interesting game comparisons...
Nintendo Land (bundled about 2/3 of the time) vs Wii Sports (nearly always bundled)
Nintendo Land: 299,731
Wii Sports: 450,584
Unsurprisingly, Nintendo Land isn't doing quite as well. This is to be expected.
New Super Mario Bros U vs Twilight Princess (Big franchise Nintendo IP battle)
NSMB U: 316,344
Twilight Princess: 367,934
This is a little more surprising. Whether it's due to a stronger third-party lineup on the Wii U, consumer tiredness of 2D Mario in the last couple of years, or early adopters of Nintendo systems tending to prefer Zelda over 2D Mario, it's not obvious, but some would likely use this as an argument for lack of innovation in 2D Mario since NSMB (or NSMB Wii with its multiplayer).
ZombiU vs Red Steel (Third-party new IP from Ubisoft that shows promise)
Red Steel: 113,321
This is probably within the margin of error in terms of fluctuations in the market. That, or people are a little more cautious after Ubisoft's track record with Red Steel. I anticipate that week 2 will be the informative week, with regards to whether ZombiU is destined to perform better than Red Steel.
Black Ops II vs Call of Duty 3 (CoD cagematch, next after ZombiU for Wii U)
Black Ops II: 77,238
CoD 3: 43,534 (sold 2.16 million worldwide)
Looks like Call of Duty on the Wii U is doing better than it was on the Wii, although CoD 3 was prior to the MW explosion. Some other comparisons with other Wii CoD titles...
CoD:WaW: 37,829 (sold 1.86 million worldwide)
CoD:MW:RE: 32,334 (sold 1.46 million worldwide)
CoD:BO: 56,658 (sold 1.22 million worldwide)
CoD:MW3: 55,289 (has sold 0.53 million worldwide so far - will probably make about 0.57 million by end of holidays)
So Black Ops II has had a good start in the US, based on history. My resulting worldwide prediction for BO2 WiiU? 4 million.
??? vs Super Monkey Ball: Banana Blitz
There doesn't appear to be anything to compare Banana Blitz to. It was the best-selling Wii title in launch week in the US other than Wii Sports, Twilight Princess, and Red Steel. I suppose an element of its appeal has been taken by Nintendo Land, but it's not a fair comparison.
Madden NFL 13 vs Madden NFL 07 (battle of the annual football title, US edition)
Madden 13: ???
Madden 07: 44,485
No data is available for Madden 13. I doubt this is due to insufficient sales, as Epic Mickey 2 for PC has managed to register 156 copies sold, and it's highly unlikely that Madden would sell less than that, considering the Wii version of Madden 13 managed over 20,000 in its first week and more than 35,000 in the week the Wii U launched. This is something to update if data becomes available.
So based on numbers so far, the Wii U does seem to be holding its own in the US, compared with the Wii. It isn't outperforming, but we cannot yet be sure whether this is due to less stock or less demand. The main upside so far appears to be Black Ops 2, which is performing more strongly than its predecessors on the Wii, despite its install base limitation. And to those who liked to compare Wii game sales with PS3/360 game sales by comparing attach ratios (in order to denigrate the Wii versions that sold better but not extremely well), I thought I'd point this out... Attach ratio for PS3 BO2 is 10.3%. Attach ratio for 360 BO2 is 11%. Attach ratio for Wii U BO2 is 18.8%. Not that this actually means anything, of course, other than the fact that the Wii U has a smaller install base.
As more information comes to light, regarding European and Japanese launch sales, it will be interesting to continue the comparison. And if anyone has ideas for other comparisons, feel free to post them - I claim no ownership of the updating of this thread (although I'll certainly update myself if I find more worthy comparisons).