Over 10 million copies sold. The only other WRPG that has done that recently is Diablo 3.
After that you have like Borderlands and Fallout 3 with 6 million, and ME3 and DA1 with 4-5+ million.
There is a chance Borderlands 2 will end up a bit higher than Fallout 3 did, but WRPGs have very long tails on average, so we won't be able to tell for a year or two.
I'm not sure if we're counting Fable as a WRPG anymore, but that also does in the 4+ range.
But yeah, if you're being inspired by a WRPG that isn't an isometric loot game, that's pretty much the prime choice financially.
Well , it would be the prime choice IF you still are into the delusion that aping some other popular game is the best way to improve your title's popularity.
In the real world, that almost never works.
Then again, there are people making arbitrary links between cause and effect all the time, so we still hear stories like "Mass Effect became more and more popular while it became more and more focused on shooting, so less RPG sells more".
Which always sounds a weird kind of argument to me, because becoming more popular with successive releases is what you would expect from ANY successful franchise, *regardless* of its direction, unless developers screw things in a blatant, self-evident way.
Complaints about enjoying the new chapter more or less than the predecessor usually come sometime later.
This isn't the Tomb Raider thread.
That said, I think you're forgetting one important thing about this chase. It actually worked really well for Battlefield (17 million), Medal of Honor 2010 (6 million), and Homefront (3 million).
Who says "it worked"?
Battlefield actually built its popularity over the years, it was a cult hit on PC and all things considered BF3 still was fairly different from Call of Duty overall, plus those few analogies with that franchise were actually some of its most criticized aspects (pretty much everyone agrees that the single player campaign was shit, for a start).
Medal of Honor Allied Assault was one of the most popular shooters ever made way before the first CoD was published (in fact it's largely from the same developers) so the name carried some weight by itself and the new installment was marketed *heavily* by EA, even tied with the promise to access BF3 beta.
Homefront was generally pointed as a financial failure. Maybe it broke even over time, but that's far from being a big hit.