For real combat moving sideways while slashing forward is preatty stupid. Even the lightest of armours could easily withstand such a wimpy strike, and an unarmoured oponent would at most get a shallow cut.
Also.... Real swords are heavy! When charging in one direction only a really skilled fighter would be able to divert that energy in another direction. What you are suggesting however is to divert your own energy sideways of the direction you are charging, whilest the energy of your sword continues forward. This is compleately rediculous, because what you are essentially doing is splitting your momentum in two different directions, and will therefor not get any significant power in either one of your actions. Not to mention that you will throw yourself of balance, and render yourself at the mercy of your enemy.

Likewise shooting two arrows from a bow at a time is equally rediculous, as each arrow will only be launched with half of the power a single arrow would have. This is because the energy of momentum the bow has to offer is split in the two arrows. When fiering a single arrow this one arrow will get all the energy of momentum from the bow, rather than just half.

It may be worth pointing out that defending and attacking is two compleately different movements, as you have to align your entire body for whatever you are doing. Charching is also different from simply attacking.

About weight. Lets say you are strong enough to easily lift up a house. Now, if you were to swing that house at someone you will be thrown compleately of balance unless you are dramatically heavier than that house, even though you are more than strong enough to lift it. The same applies to fencing. Because a sword has a bit of weight to it, you will be thrown off balance if you use it incorrectly when a lot of momentum is applied.

PS: Competetive fencing with light, whimpy practice blades don't count, as they don't have the weight a real sword would have.

Do you know the length and weight of your blade?

Not to be rude, but is it the sort that easily bends when pushed against a wooden wall? Don't get me wrong, many swords should bend a little when force is applied, but Rapiers were specifically designed not to bend more than absolutely neccesary(Without sacreficing durability), so you could pierse them through mails and light armour. Rapiers are long, thin, stiff and heavy blades.
If your sword easily bends it is a practice sword... However if it is light and stiff you have the slightly shorter version called a shortsword. This is not a weapon of war, nor intended against armored oponents, but is a easy to carry civilian weapon used for dueling and self defence.

I'm really not sure what's being suggested here. Sidestepping? We have mechanic like this already in the game. If you start charging your weapon for a moment then let go of the charge while still in the combo time period, you can take 1-2 steps to the side. This is easiest with heavy swords, but still possible with others.