I'd like to have the global availability interacting with team availability. so that when I set a global end date, I have the team availability terminated as well (or at least be prompted to have that done. Now, I have the global availability ended but the team, not affected. We need to manually change them all. 

On the other hand I'd love to have global capacity as well and have that related to the team availability and capacity. Example a person can work 8 (configurable) hours a day. Then, when planning that person in teams you can set up to 8 hours per day and any extra is highlighted (considered overtime). 

I want to have the global capacity linked to a specific portfolio as well, so that I know the total availability for the current projects and the free bookable capacity I can use for other projects.

It will be quite normal to be able to create separate portfolios as well. In the current portfolio there is no way to create portfolio - we are limited to plan and program. I am trying to manage two somehow related organisations with one portfolio and find this limiting, too.