Never had the "bug" to modify my G21. (except for a possible grip reduction)... It is not a comp gun for me, strictly what it was designed to do:
GO BANG WHEN PULLED!
For competition, I can see improving almost any factory trigger. For SD, it's a creature comfort to modify a trigger.
If it's that sloppy, regardless of manufacturer, I'd look into another more suitable. I remember the original SR9's, and the grief and recalls that followed, that's why I went M+P, in .40.
Any trigger can be improved, I figure, my G21 is fine as is.

After all, what good is the "Dark Side" unless it's "rough" around the edges.....
