Hello there, here's Johnny 
I was wondering if you guys had an idea about which is a realistic, average CTR for different GEO's, specifically for popunders and CPI.
For instance, which is a realistic CTR range that you can expect for a similar campaign let's say in Russia, Mexico, Brasil or Indonesia?
Impossible to predict. Depends on the angle, the features your LP has...
Example:
Same LP with auto redirection: CTR 90% +
Same LP without auto redirection: CTR 10%
Why do you care? CTR doesn't make you money. CV does.
I think it's important to understand which is the expected range of CTR in a given GEO, expecially if you notice that the same "package" of lander/angle/script/traffic source has such a different CTR in countries which are not supposed to be extremely different.
It's likely to be perfectly normal, but as for now I can only guess, while knowing some data of that kind it would be a different story.
Well pops are a very broad way of targeting normally, finding campaigns with mass appeal is key here.
The answer to your question is: it depends.
You'll always stumble upon variance in CTR in different countries, so will you with CR and all stats related to a campaign. There's no rule of thumb. It just depends on too many factors. An adult lander will yield better CTR on adult traffic most of the time then it will on mainstream traffic (in theory).
CTR is obviously an important factor since it drives your clicks to the offer, but CR is in my opinion more important. The 'expected CTR' which you mentioned in your most recent post is hard to determine, since it's bound to too many factors - LP burnout, competitors bids (as this effects you being shown as the first or 2nd or 3rd etc. pop in the impression queue).
Different CTRs are often enough reflected in different payouts too. Some countries fall more easy to click, some don't. It's not a rule written in stone, but at the end of the day, just calculate based on earn per view (means earn per single pop) to make up your stats.
fjk87 explained it very well - there are too many factors involved for expected CTR to be a useful metric.
As long as current CTR isn't 0% or stupid high, suggesting a tech error or bot traffic, I don't think you really have much to worry about.