A few comments from my quick dip into the Preview/Test server: It looks like the 'new' Undermountain gear we are given (right at the start before any combat) is the same item level as the Vistani items we received in Barovia, usually 644 item level from what I am seeing. (Unless these are just placeholders, as it seems the flavor text and abilities are suited for Barovia, damage against undead, etc.) [What happened to the Apprentice Armor sets Cryptic was talking about we would have to restore 'from their ruined condition.' I thought that might be our 'starting' set.
[I might have my alt do this first at launch, as your first character gets the armor with level 8 enchantments, and your following characters get level 6 enchantments. My main has better enchantments than 8s....]
In the collection you receive, it is certainly nice to get starting "companion gear" for your companion so those slots are not empty- (I had already picked up three inexpensive +3 "companion gear" items from the auction house, which are much better.)
Certainly having 12 or more open inventory space will be a big deal; I was not prepared, and Neverember quickly gives you a full set of stuff, whether you need it or not. Trying to move things around with 12 things in your overflow bag was a pain. Especially if you want to pay to remove enchantments, (which will need inventory space,) etc.
In prep for next week I need to grind some things, and donate stuff in the guild bank! Certainly I wouldn't spend time now upgrading any current equipment, or artifacts, but leveling Bonding Runestones is a good thing to do now. Collect Astral Diamonds, unlock boons, collect Refinement points, stock-up on Seals of the Brave (so you can convert them to the new seals at launch) and level all your companions to max.
Let me know if you have other questions either in Neverwinter or on these forums and I'll see you online.