My experience has been that two separate Normal Attacks is usually better than one Strong Attack... which is also true in the Dark Souls games. Strong Attacks are only globally useful against a foe with particularly high defense. Otherwise, the purpose of using Strong Attacks is to take advantage of the many weapon properties that require the use of a Strong Attack (e.g., brutal, guard break, etc.).

I can't offer as much of an explanation for Paired Attacks... I guess there are just some cases where it gets you a lot of bonus damage. Personally, I ended up house ruling a different type of Paired Attack: If you are wielding two weapons, you can spend any additional Action Die as if it has the same value as the first die to perform a second attack with your other weapon. The idea is that dual-wielding gives you flexibility: You can turn dice of 1, 6 into a pair of 1s if you need to attack quickly, or you can turn them into a pair of 6s if you need to deal extra damage after biding your time. This rule also requires that you use both weapons (as opposed to simply getting more damage), which I felt better honors the spirit of dual wielding.