Seems there have been a handful of F100 incidents - these airplanes are getting a little old now, production ended in 1997, so the latest airplanes have been flying for 12 years.
Also, I assume they're predominantly used on short commuter hops with quick turnaround due to the fairly short 1700 mile range, that probably puts alot of cycles on the airframe and gear and subsequently more wear and tear perhaps?
Incidentally though, I only count a few landing gear problems - there was one in Dallas where the RH
main gear failed at the torque link, then one belly landing in Campinas, Brazil.
The gear collapsed in another incident after runway overrun because of snow in Tehran so that one doesn't count.
This latest incident in Germany makes a count of three 'catastrophic gear failures' for the F100 - not exactly a plague, still not ideal though.