My new motto is "Nobody knows what they're talking about" including me, so take this post for what you will.
A fact of SCV, however, is when the player reaches yellow, a weak attack (I believe 20 hit points and under) will only do half damage. Strategically speaking, a strong attack will end the match faster. Sticking to safe, weak attacks are going to take twice as long. I believe this feature was used to balance the game and make matches closer. These are your options...
When they're in the Yellow:
- Try to grab your opponent, which should be enough to beat your opponent or at least set it for a 1-hit kill afterward.
- Use strong, unsafe attacks to win the match or be punished. High risk, high reward. An even better idea is to use a strong attack after you have successfully dodged or used a Guard Impact. Successfully launch them in the air and following up with a combo should be a guaranteed win.
- If you have a filled gauge, use a Critical Edge or a Brave Edge attack and that should be enough to defeat your opponent. This works especially well if that Brave Edge gives you advantage on block. Never use your Critical Edge unless it's guaranteed, for wasting your gauge is never a good idea.
- Use fast, safe moves to win the match without being punished, but will take longer and could cost you the match.
- Ring outs are guaranteed to win even at 100% health! take advantage of this if the opportunity presents itself! but aiming for them might get you out of the ring instead.
As to your problem, I see this all the time in more fighting games than just Soulcalibur. The most common mistake someone makes is once they have their opponent dead-to-rights in a match, they for some reason do not take advantage and I watch as their opponent, almost defeated make a complete comeback and 50% of the time in this scenario, they end up beating the one who originally had 60%+ health before this scenario has begun. After observing this scenario several times, there are quite a few reasons for this, and here is my personal list:
Having the advantage:
- They are trying to get an "epic finish" and attempt to win the match with a move that is clearly not working.
- They begin to "toy" with the opponent by playing keep-away or trying to dodge in a special fashion, in hopes of taking the opponents life after they get frustrated or give up.
- The opponent, knowing their defeat is nigh, becomes enraged and transforms into a monster of pressure ultimately putting their enemy (you) down.
- For reasons unknown, the soon-to-be winner freezes up and loses the match out of pure hesitation.
In my experience, these are mental scenarios as to what your opponents are thinking when you are about to win the match, and typically they fall into only one category per player, but some are known to switch.
Opponent's defeat incoming:
- The player becomes overly aggressive in a last ditch effort to win. They no longer defend, they try to pressure you into losing. They typically aren't thinking so try to dodge and/or counter.
- The player becomes extremely defensive, in an attempt to frustrate you and capitalize on your mistakes. They typically block way too much even when it's their turn to attack. They also stick to safe moves that you can't punish. I'd say go for a grab. If they keep ducking, get close as if you were to grab and instead blast them with a mid-attack.
- The player gives up. Don't waste time, don't try to provoke them into fighting more, just finish the match.
- The player "pretends" to give up. They wait for you to attack, counter your move and play the waiting game again. Just simply play the waiting game with them. When you have more health, you have the advantage. Let the clock run out, and they will eventually come to you (even if it's a few seconds before the timer runs out) and attempt to attack. Or you could try to safely hit them from a far distance away, especially if they lay on the floor.
This should be enough information for you. I am just speaking from my own experience. I don't claim to know what I am talking about. I am making an educated guess at best or a shot in the dark at worst.
I will say this; when I stopped playing Soulcalibur 5, I had an 81% win percentage, fighting a majority of players with a variety of skill levels, so take my advice for what it is. Good luck.
