The IineExtender transformer would be improved by having a forward and backward extension length.
Currently if you want a line extended in a single direction, you need to use a LineCombiner attached to the original feature and either the beginning or end ports of the LineExtender.
If you want the extension length to be different, you need two lineExtenders and the LineCombiner.
Both of these can be avoided if there is a forward and reverse extension parameter and then the Stretched port will have the desired feature without having to rebuild the line.
Bonus option would be a parameter to control whether the end vertices are moved, or an additional vertex added
