Right now, the only attack I can comment on is the Omnislash V5. I originally argued that it was unnecessary and long and would amount to the same total damage as the regular Omnislash if it even made it that far.

I, however, have developed a theory as to how the Omnislash V5 works and why it is therefore not completely ridiculous.

Like most entertainment projects from Japan, the powers of the heroes of these stories typically derives of spiritual energy. Since we know that the Lifestream is composed of spiritual energy, we then know it is part of the story.

Thus I've theorized that Cloud extends his own spiritual energy into the blades before releasing them into the air (this allows them to hover momentarily as he jets from one blade to the next). Since his energy is equally distributed to each blade, Cloud must utilize each weapon in his attack in order to unleash his full power. In this way, we see a contrast between the original and the V5.

Like in the case of Ichigo from BLEACH, Cloud's newest attack better channels his power thus accomplishing maximum effectiveness with minimal expenditure.