When will SE release an addon SDK?

[Nayito]

When is SE going to relase an SDK for ARR so we can make addons?

When the game is running perfectly. since as you say it is an "addon" not a core feature of the game. you don't need to see how much your DPS is to start attacking a mob.

We need addons when the game launchs

No we don't. We need the game to be playable and fun.

Normally i don't respond to inane comments, but please what is your reasoning for not wanting addons at launch?.

Because SE won't divert personal and resources into an addon feture when they are testing if the servers are stable