In and of itself, the 1m in 8 weeks is pretty good actually, as it seems the sales picked up once people bought it during the Xmas period.
Despite the fact that 2013 TR sold 3.4m in 3 weeks (05/03/13 - 26/03/13), the pro-rata reduction in sales due to limited platform release was something SE would have factored in, so that should not concern them too much.
What I worry about a little is that by August 2013 TR sold over 4m units, but that the producers of TR said they only reached profitability at the end of 2013.
It's therefore pretty safe to assume that, MS investment not withstanding and with rising development costs, ROTR would have to sell at least 4/5m copies to become profitable.
It's also safe to assume that Sony sales won't be as high as last time. A small % will boycott the game because of the exclusivity deal, whilst others will simply have moved on by the time the game is released. That's assuming it'll come to both gens of Sony's machines (which I think it will).
All that suggests that the only way SE will make profitability is if there's significant take up of the game on other platforms. I hope so, as it's great. Alternatively, the investment/moneyhat (depending on your point of view) will need to have been significantly higher than the $10m I've seen knocking about. To me, $10m seems absurdly low so I'd think it would have been more.
Lot;s of assumptions in the above, but just my ponderings/concerns.