Well, had AoD sold 200-300k copies (not that anyone on the dev team expected it), we would have made a sequel. Not because it takes that much money but because it would have meant an overwhelmingly positive response that would simply demand another game in that setting (and even if it sells half of what AoD sold, it would still be ok).
DR - same story. Right now all possibilities are on the table. It can fail (as it doesn't have the aspects that many people liked about AoD), it can do ok (as we hope), or it can do surprisingly well, creating a strong demand for a sequel based on a certain ending. Naturally, we can't drop the CSG and start pumping out dungeon crawlers, so we'll have to expand the team to be able to do both. Expanding team is both risky and expensive, hence the need to do really, really well. How much? It's hard to say at this point as this game will be much cheaper (under $10), so it will require a much higher volume to add something to both the CSG budget and the budget to expand the team.