I'm going to give some comparisons in my venture into the 360 version and the Xbone one that I got to play for a week or so.
Firstly, the graphics is like night and day. On the 360 there's a lot of drop in textures and stuttering that you don't see in the next gen version. That's what was most glaring to me. Also, I for awhile I thought there wasn't any option to give your Inquisitor scars. Turns out that's only on the 360 version, which I found mildly annoying.
Secondly, I had dumped probably 150 hours into DA:I across three different playthroughs so I had the maps down in my head pretty decently. When I started playing on the Xbone, the biggest thing I noticed is the amount of, well, trees. For example, after playing so long in the Hinterlands on the 360, I had a good idea where most relevant things were and how to get to them. When I started playing on the Xbone, I was lost for a good couple minutes just because the landscape had changed so radically. It was pretty jarring, but certainly a more welcome change.
The biggest complaint out of everything is the drop rate for tier three upgrades. Granted, there is a particular way to farm for them in certain locations, but that can become very time draining, never mind losing the number of chances you have for drops depending upon how many items are in said container. While some chests are static, a good many are not.
Don't play a dwarf if you like your romance options to be very few.
I hate Sara. Like, I REALLY hate her and I could go into a full-length about just how much I hate that character and often wished there was some way to kill her off. Sadly there was not, only the option to tell her to screw off when you first meet her.
Archer Rogue + Assassin = Overpowered as Hell Build.
Mage + Knight Enchanter = also Overpowered as Hell Build. Both of these builds need to be nerfed big time. Otherwise the game lacks any real challenge. The Archer/Assassin especially so since you can simply snipe enemies from a distance and because the AI only reacts within a certain distance, and you can shoot farther than that distance, most enemies will just stand there until dead. I killed a dragon that way. While fun the first time, it started to feel a bit cheap after awhile. The Knight Enchanter is OP simply because by taking the right passive skills you never really lose any barrier strength. Couple that with an armor mastercrafted with Enchanted Obsidian(which gives you 3 armor per hit)and you're nigh-unkillable.
The item duplication(much like the money trick in DA:O and DA2)makes farming for materials stupidly easy. So long as you have one of an item, you can replicate that to infinity and beyond. I may of crafted myself 30 Essences of Perfection simply because I could.
Killing Samson is a guilty pleasure. Because that guy is a total tool in DA2 and DA:I.
Legion of the Dead armor is pretty awesome. If you're a dwarf warrior. I believe it's the best overall armor in the game. Why that would be reserved for just a dwarven warrior is beyond me, but most tier three armors fall just slightly short of it.
Just some thoughts. It's a great game I find and I don't think I've completely done everything there is to do in it. I'm curious how the DLC for it will be. It's a BioWare game by EA, OF COURSE there's going to be DLC. Maybe they'll make Harding actually romancable, because she's such a damn tease.