I don't know how the measure is worded, but I would guess redevelopment to the same capacity would be allowed and exempt from the growth limits (i.e. an old failing single-family house would be allowed to be replaced by a new single-family house, an old 30-unit apartment building for a new 30-unit apartment building, etc).  If it isn't written that way, then it should be. 

It's the explosive growth that they're trying to slow down to something more reasonable so it doesn't grossly change the density and make-up of the community.