Are there any tools to simulate/gauge DPS?

[Reiker]

Yes... your primary hand gets a damage bonus. Every time you swing your primary weapon, you are guaranteed to hit for at least whatever that damage is, unless you miss of course. If your damage bonus is 11, then you'll always hit for x damage + 11. Off hand doesn't receive this bonus, which is why "fastest in primary" is suggested so often. The faster you swing your primary, the more times you're applying the damage bonus. This is why I hated the Wurmslayer. I believe it had the standard 11 damage bonus at 60, but swung on a 4 second delay. That means in a minute, without haste, and all hits connecting, you gain +165 damage through damage bonus. One minute, no misses, no haste, a fine steel dagger gains +347.37 damage through damage bonus. This is why the Mosscovered Twig was so badass at 3/10, that's +660 damage every minute (no haste, no missing) from damage bonus alone.

There are certain circumstances where best ratio in primary and fastest in secondary is more dps though, depending on how bad your fast weapon is, and if you're a rogue. This is why parsing is nice.

And lol if you still think your arms don't swing independently.