Getting stuck around stage 2700 / level 250

*EDIT TITLE: meant level ~1250

I'm running a Druid and a Sylphid and things have slowed down to a creep for me with getting more metals for leveling further. It seems that everyone is steaming past me with regards to the others who I've been challenging before. Am I missing some artifacts or units that make things pick up steam at this point?

Right now I'm running Senior Druid @ 1270 enhanced; Senior Sylphid @ 1260 enhanced; Senior Pilot (secondary core); Senior Steam Punk (secondary core); Senior Aladdin (seems to help rocket gold collection); Senior Battle Drummer; Senior Hoyden Goku; Sylphid; Hoyden Goku; Fairy. Haven't seen any Priests yet.