https://forum-en.gw2archive.eu/forum/game/gw2/October-15th-balance-skills-updates-preview/first
In the thread above i think Anet started something really good and i would like to encourage them to continue down the same path.
A while back i read a post by an Anet employee and he/she (cant find it now) stated that most changes are final about 4 weeks before they are released. This means that most of the 15th of october patch is set and whats left to do is mostly balance and polish and ofc the actual coding/design/QA.
So why not post the 15th of October patch and specifically the profession related changes that are coming.
This would allow the community to give feedback on the balancing, like cooldowns, duration, damage, range etc.
Im certain that the community can behave as good as i think they did in the link i included above.
The main reason, I think, is because they don’t want to hinder their ability to make last-time chances. Imagine the QQ if a change is ‘promised’ but does not actually arrive.