Hmm i did not know you get 2 specializations ... nice to know, thanks X Equestris 
Berserker would fit then considering the Dual wield and with Daggers my Warden has a fast attack speed so that would help out combined. And yeah my first character is for the most a good person so i will assume that Reaver is indeed not reachable for me this time. ( Guess it is more for a Rogue/Assassin type Char then. ) Would the Defence part of Champion work while Dual Wielding ...or does it require a Shield? ( Or is it a simple +% to armour? )
As for taking Templar for now ... I guess I could backup my save games and simply try out Templar. If I then find out I do not like it I can use the backup. Would mean replaying everything I did after the backup, but that would be better then being stuck with Templar from there on.
Thanks Lavaeolus. 
You get two specialization points, one at level 7 and one at level 14.
Reavers is unlocked by a certain moral choice you make during one of the main story quests, and it is acquired by making what might be considered the "evil" choice. You could save before making your choice, acquire the specialization, then reload, but you need to play through that part of the quest again.
Champion works with dual-wielding, but it is really more of a support spec. I believe there is only one active ability with Champion, and while it does knock some enemies off of their feet, it isn't that great.
Berserker could work, but you need to complete the Orzammar quest line, which is easily the longest in the game. It's also probably the hardest of the main story quests.
As far as pure damage dealing, Berserker and Reaver together would let you do a lot of damage, but you would have to wait until you had beaten most of the game to get both.
As a side note, once you unlock a specialization, it is permanently unlocked across all playthroughs.