I think you'll be hard pressed to find much information on the forums regarding the class... but I will let you know the few things that I have learned already.
1: Depends on how you want to play I guess... if you want your pets to do the majority of the work then go the warrior tree.... but i've heard that summoners are more of a debuffing / support role because we can't seem to scale for damage as high as the other classes....
3: You need to use a 2-h ret. as far as i can tell... our passive bonus increases the patk/matk for us and also our pets.... i've tried using a bow with more PATK and it dropped down HARD for my pets.
5: Refer to #1 as the type of cloak/accessories would depend on how you will ultimately try and play
8: Have a strong DD alt that can help carry you.. summoners are awesome, or else i wouldn't play one, but its a long road