Is for those that don't know how to script but want the functionality.
I personally like the log viewer as it's implemented on NoNameScript. Unfortunately this full featured script is no longer developed and it needs to be upgraded and fixed to work correctly on mIRC 7, but is by far the best full script I found.
If this kind of view can be implemented in mIRC will be awesome. And of course, let it to be changed via scripting.