Well from what I've read the heavy weapons seem the most useful, and I'd assume most Iron Warriors will wanna play a havoc. I don't know if that will stay the same upon release though.

Alpha Legion > Night Lords > Iron Warriors > Loyalists > Word Bearers

Oh, I even forgot Alpha Legion. Well, I have no clue what those dudes are gonna do.

Please tell me you're joking.

Whilst I have little to no respect for Lorgar's kin, I think no one who calls themselves a champion of chaos would put any loyalist scum above any chaos legion.
Also, I wouldn't put Alpha at the top just cause I don't think they'll have enough players. More players is more chance to form a good team

Wtf is with all the WB hate?

Seriously, where is any of this coming from?

Well, they are notorious for being the weakest of the 20 legions. Whether it's true or not depends on your perspective. Personally I believe that only the IVth is noteworthy

Because they are warriors. And we are priests. Warriors do not like priests. Unless they need heal. Then, they suddenly love priests

Only primarch is notorious for being the weakest. And only pre heresy

And he wasnt actually weak he simply lacked practice!

Or even the will to fight. Like at all.