I found gold to be quite difficult (~8 tries to beat), and have yet to get past Wave 8 on Endless. This is coming from someone who beat Mingus Diggs in ilvl 508 gear.
IMO, our reliance on big cooldowns and inability to do multitarget DPS outside of CL really hurts us in PG. Not to mention loss of Haste and Mastery making Mastery/Echo procs far less consistent. Just have a look at the rankings-
http://www.wowprogress.com/char_stat...ield.pg_damage
Only 5 shaman in the top 500, and none in the top 100. I'm honestly amazed by the guy who was able to get to Wave 48 as Ele. No clue how he did it. Maybe clever use of Thunderstorm to push dudes into CL bounce range? >_>