Personally, I'd say I'm cautiously optimistic about the 8 ability slots. I know they're not exactly the same type of game, but I find MMOs with such limitations (from EQ to WS via GW) tend to make things more interesting than your WoW style 86 abilities on 15 hotbars. Putting restrictions on things like the number of abilities available at any one time can actually increase the depth and thus enjoyment of combat. That's not to say Bioware will achieve this with DA:I's combat, but it is possible.
Do less ability slots give us less options in combat? Yes. Is that a bad thing? Well, it depends. Giving less options is not neccesarily a negative thing, it's not neccesarily "dumbing down", provided the options we have left, the choices we have left, are more meaningful than before. To take what I regard as the perfect Bioware example: weapons in the first two Mass Effects. In ME1, including the modifications, you had somewhere in the region of 562892 different weapons of each type...actually, no you didn't. You had two weapons. Either you focused on minimising heat for a sustained output, or you ignored heat and focused on getting the most damage out of a single shot. In terms of how they play you got two weapons, that was it. Those weapons did get better over time, but gameplay wise they did not change. With DLC, even ignoring the starter guns that are outclassed by later ones, ME2 had 3-4 genuinely different weapons with different playstyles in each class of weapon. Far less options on paper, but significantly more actual variety in practice.
The same can apply in combat - given players less options on paper makes the choices between the options we have left far more interesting. I dunno how many people have played both, but compare the original XCOM (UFO Defense) with the recent remake (Enemy Unknown). In the former, you have far more freedom in what you do with your soldiers in battle, as it works off an action point system where you can take whatever actions you want provided you have the AP. In the new game, you get two actions a turn, and, barring a few abilities, if your first action isn't a move, you lose the second. Now, obviously, the former gives you far more freedom in how you play, far more options in what you do. And at first, I admit I did see the change as dumbing down. But as I played more of EU, I began to realise that by constraining my options, I was forced to make far more difficult, and therefore intersting, choices. In the original, I could have a character leave cover, take a shot at the enemy, then move back into the cover, remaining safe. In the remake, if I move out to take a shot, I can't get back into cover. So such a move is no longer a complete no brainer - do I take the risk of exposing my soldier to take a shot? If it kills the alien, I'm fine, but if it misses, then he's got a clean shot back at me. What was a complete no-brainer under the "freedom" model, now becomes a serious decision under the "constricted" model. And, for me at least, it's decisions like this which make tactics and strategy fun. Is it all positive? Of course not, there are times in EU where I miss the freedom of the original. There are advanatges and disadvanatges to both systems. But to suggest that one is worse simply because it provides less options, which is what some people here are saying, is stupid.
Personally, from what Bioware have said, I see the 8 slot limit in DA:I to be an attempt to achive this kind of effect - to reduce options in order to make them more meaningful. To force players to make genuine choices in what abilities they're using, and therefore make things more interesting, challenging and enjoyable. Will it work? Dunno. I certainly hope so, and as I said at the beginning of this post, I'm cautiously optimistic.
I certainly don't see any evidence that this is a deliberate "dumbing down" of the game for these mythical stupid console players who can't use a real UI...