Draenor is lagging again, fix inc?

Almost each day I'm with annoying lag on Draenor. For me it kinda ruins playing the game (it's alot of fun, and my Warlock is awesome .. but this lag is making WoW a really annoying game for me).

I had this for over a month ago, almost every evening I get 1k to 5k ms latency. In short words, this basically means I have to wait 1 to 5 seconds before any action responds. So dotting up a target with instant casts aren't instant anymore.. but on a 5 sec cast (or longer). This is exactly what's ruining the game for me.

So I made a ticket about it and the person told me that they're looking into it. This was over 2 weeks though and it's still lagging alot. I'm also wondering if Battle.net isn't the cause of it aswell .. I read a bit about it and last time on maintenance day the Battle.net servers were down too.

WoW is a big game, if it was a small one I'd expect lag here and there, but not on a game like this though. I find it strange that it's not being resolved quickly.

So as I speak I'm having 5k ms latency again, after maintenance day.. which should make sure servers won't turn instable .. right? An unstable server lags and disconnects players. This is what's exactly going on (except for the dc/s), why have a weekly maintenance when it's not helping or making things worse? Maybe I'm clueless on this.. but please correct me if I'm wrong.