I think, that unless you use lenses for shooting resolution charts, it does not make sense to switch, unless you want to get a Summicron, which is quite similar to your old Elmarit, but with better bokeh yet. Another option, which would make sense, but only if you are a colour landscape shooter, would be the Zeiss 85/4, which is a completely different, modern look lens with high micro contrast , great flare resistance and strong colours.