Are there really no imperfect people in heaven?

OK, quick rant here, in the last couple of months I have come across two different evangelistic messages (and it's not like I read a lot of them, being already converted and all!) which have as a central premise in their description of the human problem of sin the fact that we cannot get into Heaven because we are sinners and only perfect souls/people can get in.  There are huge problems with this for all sorts of reasons but the most glaring one is that such an idea contradicts the Bible even upon the most cursory and literalistic reading.

[The Ascension of Enoch, from here]

Three people are recorded in scripture as bodily going to Heaven to be with God.  Enoch (Gen 5:24), Elijah (2 Kigs 2:11), and Jesus (Acts 1:11).  How many of them were perfect, or were perfected before they were "taken up"?  I count one, the other two were presumably as flawed as the rest of us.  This fundamental tenent of some evangelistic tracts is thus fundamentally wrong.  Not being able to "get into Heaven" for one reason or another is not a part of the human problem.  If God wants you there, God is more than capable of getting you in!