Stuff has been added from Beta to Retail, its just they didn't add anything new for lower level people. Supposedly there are class quests that are supposed to appear once you get to a certain class level and its 'supposedly' similar to FFXI artifact quest (A long quest line with a story which inevitably ends in rewards designed for the class, probably just Guild Marks though). I'm guessing those will appear around lvl 18-20 because the first Guild Mark ability is gained as 'optimal' at that point. There are at least 69ish new quests in game outside of the standard tutorial quests (they have all been datamined, at least their names) and the two quest lines from each nation, and each nation supposedly got more stories added on as well but no one is high enough to see what they are yet.
Outside of that yeah not much has changed. The game 'feels' more stable to me, the UI lag is all but gone with exception to when you are trying to start a conversation with an NPC (slight 1-2 second lag to get the menu up, but once the item menus are up their is little to no lag), the Guild Leve timer went from 48 hours to 36, you still get the same 8 + 8 local and regional guild leve limit, the NPC's seemed to have had their items changed along with their items (most seem to cost more). Rewards from nation quests are toned down and they removed all but the most expensive shield from the NPC's so unless you want to farm 400k gil, you probably want to find a crafter to make you a shield (good luck!). Basically if you had a problem with the core gameplay during beta, you will have a problem in early retail. Thankfully I enjoyed myself in Beta and actually just played sporadically. We might also have a patch on the real launch day, this is pre-release after all but even if we don't the game, in my opinion, is more then playable. Just get some friends and work on crafting with each other so you can all get properly geared since the market ward is sure to be a wreck for a long while till they get some form of item search in.
One thing to note that does make a huge difference between beta and retail... the UI lag nearly gone and the sense of permenance makes all the difference in enjoyability. The game is a grind, just as much as FFXI and perhaps even more obviously since almost everyone is soloing in the early levels. Grinds suck, but they suck even more in beta when you know the grind is pointless. Getting levels actually feels like you are getting somewhere now just purely because of that psychological reason and it changes the enjoyment factor a ton.