ArenaNet, according to the latest NCSoft quarterly report, has grown to 176 people and that number has been growing steadily since 2007. Staff costs at ArenaNet were the biggest drain on NCWest's bottom line, indeed one of the biggest costs for NCSoft as a whole, aside from the NCSoft staff in Korea.
I hardly think they'd continue to hire staff at that rate and not be working on GW2. That is the only game ArenaNet has! Compared to other NCSoft titles (or even most other games), that is a BUNCH of people. Clearly, a lot of effort is being put into the project, especially since they mentioned expanding the entire game concept over what had originally been planned when they stopped major work on GW1.
If GW2 is much more than just a "fixed" GW1, which seems to be the case, then they will most certainly want to keep GW1 running along with GW2. To do that, minor additions are needed and the GW1 Live team is slowly expanding (they need to hire a Xunlai Auction House Designer/Manager for GW1, please).
GW2, from what little has been released, also isn't "human centric" (bleh, who wants to be a Charr?), so will most likely be very different from GW1 in setting and character types, so keeping GW1 around makes a lot of sense. Just like Lineage I (1998 release) is still around even though Lineage II has been out since 2003! GW1 still brings in a lot of money, so hopefully some of that will be used towards GW1 and not all put towards GW2, which is getting plenty of funding from both past GW sales and investment from NCSoft's push towards concentrating on AAA titles from now on. Once Aion Tower of Eternity has been fully released in the west and is running smoothly, then GW2 will start to take center stage. They'd be stupid to hurt Aion by releasing GW2 info now. Aion, while looking and sounding great (from what I've seen on trailers, fly-throughs and in-game footage), is nothing really new. While a bit more than "WoW with wings", it isn't anything new or revolutionary in any shape or form. It will do well (is doing well in Asia), but GW2 (if it is good) will be a far bigger game in the west. While many here like to rag on GW1, most players (former and current), love the game and will be lining up to buy GW2 when it comes out.
You "GW2 is vaporware" types should crawl back into your troll caves or, here is an idea, actually go play something you enjoy and not keep spreading this doom and gloom drivel you are so fond of, i.e. get a life.