Wow, EQ1 and EQ2 are very similar according to wiki. No real reason to stick to EQ1 if you have EQ2, except for new content. I bet a lot of people play both in parallel.
Anyway, I have to disagree with you RDarken, because although critical population mass might be too low with just BMP-like expansions, you could still sell quite a few of them making them viable. The nice thing about GW1 is that you can rely on H&H to get things done. I certainly would pay for a BMP, a few missions, or even a single additional profession (provided it interested me). The main problem is that I would prefer to play GW2 and advance those chars, instead of playing GW1 which, while fun, would not advance anything... so I'd only really be interested in buying content for GW1 *after* I am done with GW2 content.
They're just better off making that content for GW2 instead, it'll sell that much better.