This is all hypothetical, I understand that google frowns upon the discussion of specific statistics such as impressions and CTR, relative to earnings. BUT, how much can a niche blog that is displaying optimized adsense ads, and generating around 200,000-250,000 hits per month expect to earn?
If you have good content, placement, your click rate should be somewhere between 1-3% * CPC = estimated earning
By using Google Insight for searches and Google Adwords tool. Assuming CPC of .5$ and CTR 1%, 200,000 page view must give you 1000$ exactly. Now as CTR increases CPC tend to drop. Taking a logarithmic scale into consideration, that much page view can generate you anything about 600$.
hits doesn't mean anything, a hit is anything, a html page, a picture, a js file, etc. If you're talking about ad impressions. Then if you can get a correct $5 ecpm it's easy to calculate, for 200,000 ad impressions you'd get 200 * $5 = $1000
The hard part is getting $5ecpm @ 200k hits. I get that much on my low traffic sites but the higher the traffic the lower the ecpm. I'd be counting on maybe $1 ecpm at higher traffic.
With that amount of traffic you should be into three figures per month earnings wise if you have a good niche and keywords. Traffic is king (organic traffic). Without traffic, all efforts are futile. Seems like you already have decent traffic, so go for it!