When it comes to something that runs at least $60 USD, had a major effect on the previous games and has been kept hidden from the fans, I'm not entirely sure.
If Bioware were as open about mechanics as they were romance, we'd be just fine. Literally the only dialogue we've had with the developers was through Patrick Weekes on the healing switch to barriers/damage mitigation.
Which is basically the only thing that really could have used an extensive dialogue, as far as mechanics are concerned?
Seriously, the healing switch is THE major change to game mechanics. the one which substantially alters how battles are approached in DAI, compared to other games. It is THE change that will mess you up if you approach combat in DAI like you did in DAO or DA2, as it requires a paradigm shift from reactive to proactive tactics (you functionally apply your "healing" BEFORE the damage happens, instead of after).
All other changes are evolutionary in nature, not revolutionary. The fact we get less abilities on our toolbar, or can't pause and switch equipment, don't get detailed tactics, and so on will not fundamentally trip us up as we start playing the game. Not like the healing switch, where we'd quickly run out of potions if we approached combat while ignoring barrier or guard and just focused on smashing faces.
Mind you, I regret losing the detailed tactics scripting of previous DA games, they appealed greatly to the coder in me, but I'm sure I'll be fine with what DAI has. My main worry is how effective the AI is at using "reaction" abilities like shield blocking, but some video I've seen has laid some of my concerns to rest (saw an AI controlled Cassandra hold up her shield just in time to deflect a mage's bolt).