Dual WeildFollow

Someone recently told me that you cannot attack twice in a row with your offhand weapon, and that is has to wait for your main hand to attack before attacking again, for example: (purely hypothetical) 3.0 speed MH, 1.4 speed offhand.

Main Hand hits, offhand hits, 1.4 seconds later the offhand has to WAIT 0.2 seconds for the main hand to hit again before it can attack, is this true?

Thought not, thank you.

Different weapon speeds for different classes with different mechanics.

Shaman: slower off hand so it wont steal windfury procs from main, slow main hand so it will take full advantage of WF cool down.

Warrior: slower off hand = higher WW damage & more burst rage generation. Fast off hand = steady rage but lower WW damage.

Rogue: fast off hand = more poison procs = more damage from poison. Also fast off hand = more procs from Combat Potency.