The answer to tactical downvoting problem?
As Dan Dyer mentioned in his comment on tactical downvoting, there is a conflict of interest when you have posted your own answer and are allowed to downvote other answers.
Despite the vote editing window being drastically reduced, the fundamental problem remains: I can downvote the other answers permanently and still benefit - my answer gets upvoted ONCE and wham, I have just made up the rep loss for my 10 other downvotes. The vote editing window fixes part of the problem, but there is a more complete fix that has the extra benefit of not preventing legitimate vote changes: to disallow downvotes on competing answers when you have posted one yourself.
The temptation to wrongfully downvote competing answers is huge. The rep loss is tiny in comparison. It has to be in order for people to continue to legitimately downvote.
- If I have previously voted and then post my own answers, delete my downvotes. Continue to allow me to remove the upvotes - I think this is fully legitimate.
- If I delete my answer it's probably best to continue to deny downvotes (perhaps even including the question), but I don't have a strong opinion either way.