Hey welcome back
Its a hard one to answer.
Came back a while ago myself and while there where changes most was the same.
I think the combat system changed, but I if it was vastly different I have gotten used to it quickly.
Fights maybe go a little faster and someone a few lvls below you can do damage.
Not sure
There is some changes to options.
Table inventory is one, I didn't like it at first but now prefer it.
Try it out.
Stats reset works to reset stat progress after you get a fanta
Angmar is back, that was a new one to me.
The Spirit Circle is meant to be closing to reopen as occupational elementalists.
Vamps closed.
Mercs was closed and re-opened in a different location in Sparkle, it and the last iteration of the vamps where quite similar.
Cool that they can specialise in a number of guru skills and switch between them quickly once they find the right trainers.
Guilds are in the process of being recoded to all use the same central code library and most are being balanced up
Getting a few new tricks etc.
A new roleplay club for ME the Daragim Aran was set up by Beregond and has developed into a sort of guild itself.
There are quite a few guilds interested in fighting each other at the minute, so its quite lively.
The grinders are much the same..
Mithas Troll camp is now 3 times the size.
Flotsam and the centaurs are very popular, an area you didn't hear much about before, maybe not many knew how nice they were.
Areas well Faerun is new and quite a popular grinder with goodies, but apparently exp is less for evil so rarely go there.
There is a shaman has some nice gear.
Raumdor is being update and has some new quests. Nice gear there too I never saw about before.
Equipment
Shields were nerfed a little a while ago.
Bows and polearms not used that much for whatever reason.
There are a few new choice items but will leave for you to find about ingame.
The auction house is a very cool addition, its in a tent in sparkle. Enter it and you get a paddle you can bid on and sell stuff.
Quests!
The tower of realms has quest orbs for each domain and most of them if not all have hints available to help you get started on those you still have to do.
There is a market quest every Wednesday in Sparkle, a kiosk sets up outside the auction tent and asks you to gather a number of item X.
Return that day with the goods and you get some quest exps, meant to be about the same size as zodiac when you finish them all.
Sure I have forgot to mention as much as I told you, but that is a start anyway.