No, it didn't destroy the game.

Got an archer lvl 50 and it takes 10 seconds to do 2 attacks?
"10 seconds" is definitely a long time. (Not really.)

Everytime you click light shot it says it can't be used right now..
Even though its cooldown is past ?
This has always been present in this game, it's due to the interface not properly keeping up due to being server side in nature.

Heavy shot is gone multishot is gone.. So archer is.. useless now ?
No, I'm pretty sure Archer is very useful.

The enemy attacks me twice before i can even shoot a second arrow.
Ok? Would you rather enemies not attack at all and just stand there?

Am i doing something wrong here or is it just that bad of a lag kind of gameplay now on the attacks ?
You're doing something wrong ontop of the usual server latency problems, but it'd definitely no worse than it was before.