I agree it's unlike Apple to have one product launch stepping on another, but this is the post PC world. I can see Apple doing a silent launch on the 15" in mid/late April and then announcing the 13" and 17" at WWDC, presumable in mid June.
WWDC is unlikely. Apple has Mountain Lion and probably iOS 6 to talk about. Throw in their demos (on existing hardware) and the obligatory "millions and billions ... buy Apple stock " segment at the beginning and that is a full keynote.
Mountain Lion is also a problem with a June launch. If Apple intends to launch ML in July, then June is likely "dead" as a Mac launch month. There is zero good reason to drop a 10.7.(n+1) port update for all of 4-6 weeks till obsoleted by 10.8.0. Apple would just wait till 10.8.0 is released just like last year (2011) when the mini slid till after Lion (10.7) launched.
If ML is on track for August or September then June would make sense. I seriously doubt ML could make June or ship any time
before WWDC. Now that Apple has somewhat tightly coupled WWDC to yearly upgrade to 10.(n+1) it is extremely doubtful that any Mac will be introduced at WWDC in the future if they stick to that schedule.
The whole expectation of "dog and pony" shows for Mac intros is deeply misplaced. They aren't going to happen regularly ( if at all in most years). Apple's stated reasoning behind dropping out of MacWorld (and other shows) was so that products could ship when ready and not be tightly coupled to "shows". Perhaps a major new Mac model but most likely only going to get evolutionary upgrades for the Mac line up. (e.g., MBP 15" that's 0.9" high to 0.79" high ... ooooo a whole 0.1 of an inch. )
If Apple wants to demonstrate that they are energized about OS X as much as iOS a WWDC keynote that was split 50-50% would be a very good start. Nuking
both iOS and Mac hardware upgrades from the WWDC keynote would be a large improvement to making that happen. WWDC can focus more on the existing systems (hardware + software combo) and the what the new OS updates are.
