So, I’ve been thinking, if we can only bring our inventory to a Siptah server when server transfers get here, what will you take with you? The obvious list:
Curious to hear your thoughts on what you should take with you.
Friends 
I don’t have any. 
I got lots of dragon powder though! 
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:
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.
Can’t you just make those at the alchemy bench when you have the recipe? All you need is Fragments of Power and oil, right?
I missed Potion of Bestial Memory especially on Siptah.
Now that we are on the subject of feats, can you get Specialist ammunition IV on Siptah?
You can but it is very very very difficult to obtain the recipe in IoS, this is why I said make sure you get the feats before you transfer.
You can but also a feat not easy to get on IoS. I will add it to my list for whomever might be reading.
I know that this situation is not set in stone yet, but…
Aren’t we going to transfer WITH the feats that we already learned on EL or Siptah?
For me the feats is All that matter when it comes to this feature. No loot interests me, only thralls and feats.
I have done a couple of vaults since 2.4, not even 25% of what Was i doing before 2.4, but i got like 7 recipes, maybe from 10-15 vaults.
Maybe i Was just lucky, but it really seems that they have increased the drop rate for the esoteric recipes. I farmed for gravedigger like mad for months and never saw the recipe, with 2.4 i got it on All 4 servers that i play( even on testlive).
I Do not know, it might just be speculation from my side.
Yes, as far as I know you keep all feats and I agree with you that they are really all that matters …
However - you have all that inventory space, so its why waste a good opportunity to give yourself a head start? 
My 64k duped dragon powder. And 2 armor sets with spare weapons.
Ofc, i have been against the opinion of other players which took this feature as “end of the pvp”. Quite vocally i might add :))
I am not going to reply on the topic because i habe been out of the pvp scene for about a year now. So pvp does not interest me currently.
Probably we going to find out more on Server Travelling tomorrow and will not be just a boring release date announcement.
“You have a dream, that someday you will not over react”
Lucky you, I did all vaults in 2.4 to test them and didn’t get a single recipe from them. I will double check the rate in the DevKit though, just out of curiosity 
God, I hope so.
I’m going to Siptah and I’m taking with me…beers. Lol. It’s an island with sunny beaches!
Yeah, too bad about all those washed up bodies on the shore. Kind of a mood wrecker. 
Well we are barbarians, so maybe we take it in our stride, while chugging beer. Lol.
HOOOORSEEEES
Grubs.
I was doing all 14 vaults daily until 2.3. But then my eldarium Stacks got lower and lower so i did the westside vaults twice. Dead Leg, Egg …, gravedigger, both tinker recipes(these were what i Was after). Even if the recipes that i got were irrelevant for me, it was good to see a recipe each 2nd vault.