Don’t forget getting feats such as Grandmaster Weaponsmith/Armorsmith, Mightnight Alchemist, Scorpion Queen Poison, Specialist Ammunition IV & A Memory of Oils because good luck getting those on IoS. Very very important to get those on EL if you are transferring to IoS PvP server.
Other feats that you may want:
Dragonbone Weapons + Silent Legion Heavy + All Religions + All Cooking (or at least the ones you need for the feast you are using) + Royal Lemurian (armor)
Materials that are harder to obtain on IoS in comparison to EL:
- Crystal (you are bringing dragon powder anyway).
- Obsidian (with the gear available on IoS, you probably won’t need that much but in case you want to try the new weapons)
- Black Ice
All the above materials are available on IoS but you can’t farm them as quickly.
Crafter thralls (especially the ones with a specific specialization), it is still easier to get what you need on EL than on IoS.