What not to include in Sitemap (and what to include in Robots.txt)

At first: Total Indexed URLs: 2361

Then I excluded Show Post pages from Sitemap

and it resulted in: Total Indexed URLs: 1169

Then I excluded Member Profile pages

and it resulted in: Total Indexed URLs: 630


My questions:
1) Would including Member Profile pages make any sense?
2) Should I worry that the number of indexed URL's dropped from over 2300 to just 600?
3) What else should I exclude?
4) The above was done in vBSEO Sitemate Settings. In addition to that, should I also add the above to Robots.txt?

Hello Marvin ,

I personally donot add showpost and member profile urls within sitemaps cause i want bots to focus on my threads instead of member profiles. Indexed number of urls are not important. Important part is your SE rankings.

Thanks much, Mert. Other than the two items, what else would be recommended to exclude from Sitemap, and what items would be recommended to place into Robots.txt?