I've been around long enough to have gathered a few enemies

Such a common claim and so often wrong.

I can always count on 2 or 3 downvotes for every node.

Over the last 8 months you've had a grand total of 6 down-votes, each one cast by a different monk. In that same time you wrote about 16 nodes so your perception doesn't match recent reality. FYI.

The current problem that I have is that I don't like to comment on stale nodes as much as I used to, because the 2 or 3 downvotes that I will get will not be balanced by upvotes, and I don't like to have too many nodes with negative XP. Will this change help with that?

Hard to say. I suspect it will help some. There might be a tiny increase in odds of up-votes going to old threads due to heavily-down-voting monks just trying to get their voteavg up. :) Likely we'll see a reduction in the number of monks who list "comments on long-dead threads" among their pet peeves that are worth down-voting for. Maybe we'll get more monks hitting worst nodes looking for candidates to up-vote.

I think it will still be fairly common (though less common than it was before the change) for a "reasonable" node to get 1 or 2 downvotes. But I also think the change will greatly slow this trend.