One alternative way to find tags with no tag wiki is to visit the **NEW** tab on the [tags page](http://stackoverflow.com/tags?page=1&tab=new).

This will give you the latest added tags and those often doesn't come yet with a wiki or excerpt. 

As you see how many questions already have the tag you can judge how valuable an excerpt/wiki would be. As a bonus you spot misspelled tags (retag those questions so the misspelled tag gets removed at 03:00 UTC) or tags that either should be synonyms of existing tags or simply be replaced by a better tag.