Tried playing it a couple of times now. Lots of weird wording. This expansion cant have been playtested much I'm afraid. Dont buy until a second print.

Do like the intention though, the flow is diffrent - in a better way!

You are severely exaggerating the problems.  There are a few minor issues that are open to interpretation, but that hardly makes it a bad expansion.  Its actually an awesome expansion and my group never intends to go back to the base game because the expansion opens up the different powers and gives them all multiple paths to victory.

Your loss if you think its not worth it because of the small wording issues on a few of the cards...

 Fill me in on some of the common and quite crucial skaven spells: Strength in numbers and Verminous horde - how do they work?

I'm guessing the faq will be surprise to most players.

Fabbe said:

Everyone in my group agrees that the intention was for Skaven to outnumber everyone else, so you have to have the most figures of any single player in the region for them to work.  I've seen all the arguments on this forum and others about the cards, but we all really believe the intention was the same on both cards (ie outnumbering everyone else).

Whatever you decide, just make a decision with your group and go with it until the FAQ is released.

 The ones causing the most grief are:

• Dial advancement counters for Tzeentch, and Slaanesh - is it once per area per phase, once per area across a whole round ? 
• Acolytes upgrade - When/how does it apply its power

The rest are fairly minor card combos etc.

Although I do think a lot of this could be avoided and also think the expansion isn't quite balanced, I still would recommend buying it as its a lot of fun.