My wife would be adamant: Leave it!
At this stage, HA is still a hobby rather than a "real thing", so it's unlikely the new owner would want to deal with any of it - many things would just be unusable by a new owner. So there is an aspect of the decision that I think would obligate me to remove much of the automation.
For myself (after tricking my wife to allow it), a lot would depend on my continued interest in the hobby. It's possible my next move is to assisted living - not imminently, but I'd be happy staying here for a long time - so there's not much chance I'd want to continue the adventure.