We were having a discussion today about weighting while lunging with the sabre. This started because in Wu style you should always be single-weighted with the full weight on one leg or the other, but if you are in the lunge position this is very hard to achieve, though possible.
However I think that while this can be achieved in a form situation it requires such a major sacrifice of balance that it cannot reflect a practice with any combat value. To lunge forward for a heart splitting stroke but to wind up with all the weight on the front leg means that you have to increase the length of the lunge so that the weight of the sabre counter-balances the weight of the rear leg. The only way to achieve this is to lean the torso forward over the front leg, and with care this does allow you to become fully single-weighted.
However, I fenced for years and one of the things which is dinned into you is to never, ever try to extend distance by over-reaching or leaning forward because you then lose the ability to spring backwards out of the way of any incoming counter attack; spotting that your opponent has a tendency to over-lunge can give you significant advantages if you can exploit it.
The counter-argument to my point is that the insistence in Wu style on single-weighting is about 'training to the max' so that if you can achieve 100% single-weighting in form work then you should be able to achieve 80% of it when in combat. However I think that developing a tendency to over-lunge in the quest of training to the max in sabre is more likely to result in an habitual tendency to over-lunge which is a fault which is not outweighed by any gains from seeking to be single-weighted.
I think that this is linked to the fact that sabre forms are somehow seen as essentially unlinked to application - in a way that hand forms are not. When you learn the hand forms you are learning techniques which you may justifiably use in a self-defense situation: few of us will ever have to fight for real with the Chinese Broadsword and so does that result in a tendency to not analyze it's technique from a combat perspective in the way we do with hand forms?