I'm fully expecting it to hit 10 million by the end of the year, no problem.
I think that people will be surprised at PS360 sales. Those who haven't jumped on the Gen 8 bandwagon don't have that much to choose from in terms of shooters this fall. CoD hits in late November, but that's pretty much it in terms of blockbuster FPSs. Destiny's gonna corner that market for a while, and it will surely be one of the best sellers on Gen 8 too.
It'll review well, there's lots of hype for it, there's lots of positive word of mouth from the alpha/beta (despite some issues) and there's probably gonna be a massive marketing push.
Load times seem a bit silly--worst I've seen on PS4 actually. Going to orbit in particular seems like it really shouldn't have load times.
I have no source for this, but I kinda get the feeling that the long load times in PvE are to match up other guardians to populate your particular game instance (just like the game tells you it's doing when you enter PvP). Not sure if the Orbit-system would tie into that, but it feels like the load times were way too variable to be just about streaming data into RAM.