It would be great if the dock could combine dock shortcuts with the icons of the running applications; if for the running application there is no shortcut on the dock then just show the new application as another icon on the dock that disappears when the application closes (same behaviour as Seven's taskbar). This way you'll have a lot of more free space and the dock won't get full with only a few applications opened.
Also, for the upcoming feature, stacks, icons contained in stacks should not combine with the running applications. Only icons appearing directly on the dock should combine. The same for icons contained in sub-docks.

I hope you can add this feature

It's high on the to-do list, but unfortunately it still won't be in the upcoming v11.5. Lots of other cool new features will, though!

Hey Jorge, just coming back to this thread to know if you're planning to add this feature in Nexus 11.7 (as we're at 11.6 now) or when could I be expecting this feature to be added ?

v11.7 should have it, together with jump lists.

Thank you very much Jorge