I have started working in the World Editor just two years ago. My custom campaign requires modifying upgrades and units from TFT campaign.
The issues I have encountered within the Campaign Editor module are:
Upgrades introduced in TFT (backpacks, Naga upgrades, expansion unit upgrades) are not displayed, making editing them for whole campaign impossible.
Units added in TFT (such as Kil’Jaeden, Temple of Tides, etc.) or in 1.32 tend to be missing fields in Custom Data tab of Campaign Editor module, even if I open a map within the campaign.
Due to these issues, I (and, I guess, other mapmakers as well) have a lot of troubles working with newer objects in data, requiring creation of new units and upgrades and copying of a lot of data manually, where just editing one field could be enough.
We mapmakers know that you are striving to do your best to return player trust in the Warcraft team, and that you’ve already added a few new functions into the editor since Reforged and 2.0 came out. Please, continue working in the same direction.
Strange… I just opened the map editor and these things seem to be present still. I found the backpacks normally and the same thing with the upgrades (Naga stat upgrades are in Upgrades → Special, for example, in the Campaign Editor’s Custom Data.) while Kil’jaeden and the Temple of the Tides were in the Units → Undead → Campaign → Heroes folder & Neutral Naga → Campaign → Buildings folders respectively.
Have you tried verifying integrity of the files? Do you have screenshots of this?