Once again we run into the issue of contradicting an established (if ridiculously dumb) FFG rule regarding concession. While I think players should be able to concede a game for whatever reason they so choose, that is not the rule according to FFG. So while I disagree with the rule, we have to be conscious and careful about how we contradict those rules.
One thing to consider when looking at rules for events is not just those players who might make the cut, but also the players who never will. New players take longer to decide what to do than old players (on average). So one fear, and this is based on my experience as a TO for the last 3 years (so anecdotal yes, but based on dozens of tournaments across several states and regions), is scaring away new players who feel that they can't even break into the game at all since the rules are now set up to penalize them.
Is is frustrating as someone who is gunning hard to make the cut to get paired against someone who plays slow and then lose out of the cut because of that? Yes, of course. However scaring away a new player is a loss for the community as a whole.
In the end I am not telling you to do one thing or another, I am asking that you be mindful of all of the players of the game, and how adding different rules to your tournament might affect all of the players.
All that being said: this is the BABW finals, at that level players should be able to play fast enough to finish in the allotted time. Just consider how it might look to others that the "top players" are now playing by different rules.