Discussed in face-2-face meeting, reached no conclusion - good arguments for both sides.
Aggregate objects can help reduce cost of testing and on the DCS side if they are reused on multiple projects and /or multiple times in a project. Aggregate types can increase cost for a server vendor, especially if they are not re-used. Folders are also a viable alternative, that is cost effective if the project does not reuse the structure often (or at all).

It was decided that this should be further discussed after 1.02 (i.e. in 1.03 when multiple MDIS projects have be developed and deployed)

At this point still not clear, will wait for more projects. Both options are being used, no complaints. But it might be a good idea to offer suggestion on when to use which (i.e. if you want an overall status the Aggregate Object helps, but if this is not needed, you add more variables overall with the aggregate object that might not be needed)