1) Are all skill trees for the different weapons the same for the 4 classes?

2) I know in Skyrim/Oblivion sneak attacks doubled or trippled damage (or even more with perks). How much in ESO is your dmg multiplied when preforming a succesful sneak?

During this beta weekend (my first) I only explored the templar's ardent spear line, 1h and shield, and bow but really loved the combo! I tanked in the dungeons, bow'd in pvp, and switched between the 2 while questing, often starting a fight with a sneak attack even tho I was a templar (playing paladin style) in heavy armor. I F***ING LOVED THE BETA AND CANT WAIT FOR RELEASE!!!!!!

1) Yes.

2) Unsure, but an extra bonus of a sneak attack is that it stuns foes briefly (disorients or unbalances, I forget the phrasing they use) so if you hit them with a Power Attack, they get knocked to the ground.

Bonuses to damage are greatly lowered in this game. You get a nominal boost for damage, crit and crit bonus from Nightblade class and Bosmer and Kajiit races which adds up to a decent chunk of extra damage but nothing too crazy as it would be over powered in a multiplayer game.