It could simply be an upgrade. Adding raw, better EVF for a start. Price suggested is approaching the lowest I have seen for the 1000.
Steve,The 1000 has a brighter EVF and the manual option is a huge asset.
There is setting in the evf so you can brighten the image, it is medium by default. Same for the monitor.
I am 83 and struggle to walk far, even made myself a walking frame with wheels, but the extra weight of the 1000 is no problem, especially when it comes to taking pictures