I do not know if this is the right place to ask or post. Is there any plan to implement or work on an activity stream like Facebook or Jomsocial for future versions of IP Board?

I believe there are some mods in the marketplace that do this.

Yes I know the mods but I would like to know if it is planned to implement this e.g. as a starting page.....

Technically you can set any application as your landing page.

In your forum root directory, you have a file called initdata.php. Open that and find

define( 'IPS_DEFAULT_PUBLIC_APP', 'forums' );

You can change that to point to any application - whether it's an IPS component or a 3rd party mod.