Will GW:EN give additional character slots?

If so, how many? If not, why not?

No new professions = no extra slots

This is an expansion for the existing chapters; not a standalone. It will not incorporate character creation.

I suspected as much.

Now, should I spring for the 10th slot and go play a 'sin? Is that worth it?

Go for it... if you want to play it... but think of this, 10 characters, going through all three chapters and GW:EN 10 times and then replaying with friends and guildies... I just deletd 3 characters and have my main 3 and my presear character and thats all I'm sticking with

especially if you think about linking your character familialy throught he hall of monuments into GW2 aswell, thats potentially 10 characters to play with in GW2, too many for me

You do not get to play your GW1 characters in GW2. But I agree with no new slots due to no new professions.

you can buy then 4 10$ or a new acess key to your acc will give you 2

Like those said before me, I'm guessing since its not technically a Campaign no new slots will be provided with purchase.

Time will tell.

If someone already has all three campains adding another key will not add any slots.