Thanks for bringing this problem to my attention. The problem makes sense and I agree that LogViewPlus should do a better job of showing Exception columns.
A simple solution here would be to calculate the height of the message column based on either the message or the exception - taking the larger of the two. Both columns should benefit from the extra space. The height will still be constrained by the user setting. This is a simple change we can put into the next release.
Just to let you know, our BETA release supports automatic syntax highlighting and pretty printing of JSON messages. Currently, this release has a bug which causes a deadlock which is preventing release, but hopefully we will be able to officially release this feature soon.