Lets throw some numbers into the mix here.
Gears of War (launched same point in time in 360's life as MCC launches in XB1's)
WW:
Userbase: 5.47m
FW: 910k.
=17% attach rate
USA:
Userbase: 2.9m
FW: 510k
=17.5% attach rate
Halo 3
WW:
Userbase: 11.9m
FW: 3.8m
= 32% attach rate
US:
Userbase: 6.45m
FW: 2.42m
= 38% attach rate
With Gears we have a new IP, obviously not as frontloaded as Halo MCC will be, but with Halo 3 we have a mainline title (that was possibly the most hyped videogame release in the industries history).
I believe the XB1 userbase end of September was 6.1m. + 670k from October (already done 470k, plus my estimates of 200k for Sunset week). + 300k for COD/Bundle/Price cut week + another 250k for Halo MCC launch week. Userbase around time of release for MCC should be around 7.4m.
10% attach rate - 740k FW
15% attach rate - 1.11m FW
20% attach rate - 1.48m FW
25% attach rate - 1.85m FW
30% attach rate - 2.23m FW
I don't see why it can't do on par with Gears (which would be 1.3m~) But this is Halo and it's hyped.
I reckon 1.7m+ (with close to 25% in the US) (1.2m)
Also think VGC will undershoot this by a big margin and numbers that come out later will rectify that.
