I actually do have some ad groups with 2K keywords. As hard as it is to believe sometimes that's the best way to do things. More often than not though that's not the case
Actually, I have 11 ad groups in this campaign with approximately 1975 keywords each. Wasn't a mess at all, until I had to create more ad groups just fit in all the keywords.
Normally These 2k keywords Adgroups has an interesting point:Only 20% of the keywords generate 80% of the clicks. After one month running you will see that there is a lot of these keywords that generate almost no clicks. Use the filter feature to isolate then an clean then out so your problem is solved. If you have 11 groups with all of them with 2k keywords each also I would suggest to try smaller adgroups to improve the quality and pay less for your clicks.
I had myself about 30 keywords for an ad group with poor results, decided to optimize it with only 2 combinations of words and 2 exclusions and I got a CTR of about 5.4%. And that could still improve a lot.
Not the case at all for me! I have a few keywords that generate a bit more and some that do less than the rest, but for the most part they all bring in similar amounts of traffic. I can see what you said being true on google and the search network. Most of my traffic comes from the content network (aka adsense), so I guess it depends on what you're trying to do.
Yes, I agree with: content network is hard to say - It does not contain individual keywords statistics, only search network is possible to see impression/click for each keywords.
Exactly, by having more keywords, you get your ads shown more often. And having niche keywords lets you target those hard to reach users.