Dandy and Persephone above are spot on.
The camera made combat really awkward. It was a weird hybrid of 3rd person action game and tactical-pause combat.
The open world needs to be planned a lot more carefully, or scrapped entirely. A smaller game, with fewer, better battles is better than a sprawling open world with endless trash-mobs.
The open world is absolute hell for player investment in questlines unless the devs plan things carefully. ME:A was even worse.
DA:I felt like walking round a shopping mall, ticking items off your shopping list while being constantly pestered by a child who wants you to buy all the trashy toys that you know they'll play with once and never mention again.
Or like watching a movie with a child who isn't interested and keeps interrupting to ask for things (can you tell I have kids?)
The strength of earlier Bioware games was that you'd have a focused quest that you cared about, while sidequests could be solved along the way. Most importantly, the other "main" quests were put out of mind until you'd solved your current quest.
With DA:I and especially ME:A, you'll have a dozen main quests active simultaneously and all at various stages of completion. You'll constantly come back to a quest, spend 10 minutes reading dialogue and trying to remember what the hell it was about, progress the quest for maybe 15 minutes, then be told to return to your base to continue the next step. So instead you switch to a different nearby quest because you don't want 10 minutes of loadscreens and traversal just to get the instructions for the next step.
ME2 was excellent due to it's mission structure, which meant that for the next hour you'd be completely focused on a single story (with a few optional side-stories involved).
I'd also like to see better dialogue. The dialogue wheels don't work when you just get lots of ways to say the same thing, with maybe a clear binary choice at the end. The dialogue feels really unnatural and 'gamey'. It doesn't make me feel invested in the character just because I choose the tone of the conversation:
Yes sir!(professional), Sure whatever (casual), We'll do it together (empathy), Just don't get in my way (renegade), Can we bang afterwards? (romance)
In contrast, the indie RPGs (Tyranny springs to mind) have done really well in making good dialogue with good choices.
So: Better combat/control system, focused quests, more interesting dialogue.