I live in Portugal (Europe), play L2 at Devianne for more than 2 years and the average ping has been always around 145 ms. Since C5 the average ping to Devianne and all american servers is now 500+ ms.
What is the problem with the connection to american servers? My ping to Teon and Franz is 80ms, so I think my internet provider is not guilty of it.
Seriously, the ping varies greatly. I have like 130 ping on Franz (which i just started playing), 100 on Lionna and 32 or so on Devianne.
I live in Pennsylvania.
I've had impossible lags on Devianne (lowest ping for me) and smooth play on Franz (highest ping for me).
C5 seems to have increased a couple a bit but i think this is normal.
Though over 9 months I've averaged a ping of just under 100 on Lionna (my home server) during C4 it averaged more like 120 for me!
I'm not sure this amount of variability is necessarily a problem.
Teon and Franz servers are now located in Germany. This should explain why your ping to these are lower than the ones in America. They moved the location to these servers w/the launch of C5.