Spaces and Rooms are not the same thing. One is for use with MEP and the other is for Architecture, they should not be bound by each other.
Spaces should have the option to ignore a room separation line. For instance, if you have a large open office area and the architect has decided to divide it up to show names for each "office" this does not help with working in an MEP file and defining a space for this area. If the spaces ignores the room separation lines, then a large space could be placed, or it could be divided up with a space separation line. What is the point of a space separation line if a room separation line does the same thing?
In the instance above, another option would be to combine multiple spaces. This would do about the same thing, but I think that just ignoring Room separation lines is a better option. Sure you can create a zone, but a zone doesn't have the same information and use as a space does, so it isn't useful in this case. Similar idea here: https://forums.autodesk.com/t5/revit-ideas/combine-spaces/idi-p/7215733
Some options could be added to a space's properties to allow it to ignore a room separation. This way you could use them normally and then if needed, toggle the option on and ignore the room lines and then create your space how you'd like.