ATCO, I think the reason you have witnessed so many variations on a theme (and by the sound of it not all of them sensible) is down to the effect modern technology has on us pilots.
Take the Airbus family. In flying one of these, one can be as lazy or as pro-active as one desires, and this is fine so long as the nav database has all the STARS/SIDS, a sensible intercept onto centrefix, and a sensible vertical profile to match.
Problem is when there aren't any nice easy approaches loaded, and you then have a choice:
a) Let the FMGS get on with it, trust you can remember the 3x table and hope that it all works out
b) Construct one or two waypoints to ease the lateral phase (turn-on) and associate a sensible vertical profile (constraints) with these waypoints
I suspect the worst excesses you have witnessed stem from the lazy option a) above.
Rgds,
dcd