1) I can't formal debate as I'm going away for a week starting Monday to visit my best friend. I'm also in university trying to major in Chemistry (any Chem major will tell you how hard this is) so I don't have as much time as I would like to have.
2) Why do you want the Brave Sword? I'm not asking "why do you want the Brave Sword instead of the Wo Dao", I'm just asking in general.
The Brave Sword is really only better when you consider it for the Funds Ranking. The Wo Dao is actually better as a used sword because it has more Crit than a Killing Edge, less weight than a KE and is only -1 Mt (which really doesn't matter when you consider that a critical does 3x the regular damage), not to mention the exact same uses as the Killing Edge. Granted, it's only for Guy, Lyn, Karel, Rath and Karla, but Guy will (probably) be in play and Lyn still has a couple of forced chapters, not to mention a possible (not probable) promotion which has her seeing something like 40 Crit without a weapon in her hands (I did the math in a previous debate on GFaqs).
PS: Just checked and it's about ~35 Crit.
Assuming that we stick the Brave Sword in our storage the minute we get it, that's 3k we've saved. If we were to use the WD instead of a KE, we save 1.3k in actual Funds (using 1 less Killing Edge), making it a 1.7k difference.
Now let's say that we use some of the Brave Sword... About 10 uses sounds right. We still have 2k saved from the Funds of the sword but now there's a 700G difference between the two swords. That's basically nothing as only 3 swords cost less than 700G (Iron, Slim and Steel). And that's after only 5 attacks (2 shots per attack before doubling).
I'm currently leaning towards the Wo Dao as being the better practical sword.
3) I'm not trying to argue Karel > Harken. I'm not an idiot. I'm just pointing out what I think is wrong with your post. I don't think that Harken is underrated at all.