It was a help for me to group in Cruma Tower (now Catas or Necropolis). It's also great if you can join clan parties in higher level areas where you couldn't solo and leach xp there.
I had no good solo spot after level 30. The mobs in Execution Ground did great damage on my char (DE fighters hate Stun and Nukes) but you have much better equip as you mentioned. After that Death Path is also nice. Only the Fettering Souls may take long to kill and can be avoided.
EG should help you exp a lot pre-35. Its close to town and mobs provide good, clean exp without too much risk for dying. Make sure you have at least competent jewels.
The Field of Whispers provides good exp. As long has you have a haste pot or someone to windwalk you, you shouldn't have any trouble waiting for mobs to respawn, just attack a large area in circles. Hopefully the Rakuls are still there from C3, great exp. Levels 35-43 about.
Death Pass is good exp as well.
And don't forget the HC and PN. Good exp, make sure you get a group where you don't draw aggro too much.