Why do this you ask? Well, there's a lot to it, here are the pros and con's to switching to Portal 2 rather than staying on Portal 1, which wouldn't be in the best interest of the mod and further development of the mod.
Cons:
We'd have to start almost everything from scratch, except for the general story and the current soundtracks we have.
I'd want to re-do some of the styles to fit Portal 2 more.
(if you know any others then please let me know because I can not think of any others lol)
Pros:
Less limits.
It would be easier for me to get back into developing, as a lot of things are pre-made as entities you can place down or instances.
If we wanted to, we could also apply to become a P2CE mod if we wanted.
We could get more talented people to work on the mod, as the mapping community for Portal 2 is larger and most people would not want to switch to Portal 1.
Me and Xelamid have the most experience with Portal 2 hammer.
The scope of P:DS is large for Portal 1, we have so many things we want to do that would be hard if not near impossible without editing Hammer itself. And we might be able to go even further now!
Yes, this means that we probably won't be able to say anything about the mod for a while, but this is a decision we have made so that we can make P:DS the best we can.
Once we get things started on Portal 2, we might apply to become a P2CE mod too, but this is still under debate. Thank you for reading and have a good day!
This does mean all of the current images are now completely outdated. We will work on this soon, don't you worry. Here is something to munch on (Not finished, not close to done either. Just something to make this article have something worth the read.);
Best wishes, the P:DS team.
P.S: We are still accepting applications for Voice Actors and mappers. We aren't accepting Writers and if you are an composer that wants to apply, it is unlikely you will be accepted but not impossible.