i'd say there 'should' be an update 'soon'. so just wait for wwdc, but don't wait too long
things to consider (against an update):
1. macbook airs are now updated, and yet they don't have force touch.
2. backlit is missing from keyboards for YEARS
3. thunderbolt display is yet not updated
so i think apple may NOT apply their latest technology to those accessories as soon as they become available.
and if they update it, i guess the difference will only be a slimmer design and force touch.
force touch is definitely a plus, but not a must