If I got this right, it is planned (in long term) to remove scopes. (at least in their current form)
In many cases scopes are nothing more than an always available app. The added value of such scopes is minimal.
However aggregate scopes (like today or nearby) are special and they are a distinctive feature of ubuntu touch.
warning: begin of wild thoughts
Maybe it would even make sense to generalize the aggregate feature so that the user can aggregate information in his own logic. What I mean is wouldn't it be nice to be able to create additional aggregate pages with all information sources that fit in this category for you. Some people would stick with "today" and "nearby", others would group everything in a new "everything" aggregate or else split it up in many different aggregates.
end of wild thoughts
Anyway - what is planned about aggregate scopes?
In my opinion it would be a capital mistake to loose them with no replacement at hand.