Active abilities in ME:A (Updated)

They've very briefly shown it, but they haven't talked it in detail at all. It's entirely possible you are locked into 3 during combat and can only switch between fights based on everything they've shown and said so far.

Again, the question was about having more abilities to use on the field without going back in the menu, since it's bad for caster classes. Ian replied directly to that, so he meant that there are more then three to use at the same time, regardless of the method and the number.
It doesn't matter that they just shown it and didn't talk about it. Hen doesn't want to talk it yet because they have plan to reveal it. It won't be a 'secret' if it refers to the switch in the menu because they shown it, it's not something they didn't reveal yet.

no I'm assuming they are going to show it off when they are ready to explain it.

Well, the tweet mention the access thing works only on SP, so while they might've make it closer to MP, it doesn't have to be limited to three abilities.
Expecially since I don't see it working in any other way then unlocking a new loadout slot in some way (since the button scheme on console is full), they can add three more powers. I do agree to be cautious, but even what they said here made me thing they had something to add more powers.

As for the reason why they didn't show it yet, I guess they might've been working on the system/the number of active powers available and weren't ready to say anything until they finalized/cleared the system from problems/bugs.

It seems the way to access more powers is by switching profiles, in the middle of battle.

Except they just tweeted about using (dynamically) profiles is determinant/very useful in tough battles, which is a big hint on being able to use profiles without going in the menu screen. Not to mention Ian's tweet about using more then 3 is a direct response to a tweet about caster classes. Squadmates aren't relevant to that.
Beside, they already said we can only order squadmates to use powers in general, not a particular one.

I understand being cautious or pessimistic, but all recent tweets point to another direction.

Why? You can create different caster profiles. 

I think those are separare things. What the CES keynote shows is just (possibly) a part on how the system works, based on their recent tweets. I don't think we can access that menu in battle (it'll make the operation too long as well), while what they said recently is about accessing more powers during combat. The last tweet about profiles kind of lean towards profile switching beside the menu.
Either way, next week we're supposed to see the long gameplay video, apparently, so it might end this debate for good.

The last tweet seems to actually hint towards switching in combat. You can't know beforehand if a fight is necessarily tough, so switching profiles in combat is useful to deal with those fights. Hence what the tweet hinted at.

So, to summarize what we know (or believe) thus far:

- In the interest of "streamlining" or "simplification", instead of having all powers available from a single interface, we'll need to manage multiple swappable profiles / palettes. This would imply the need to memorize and develop muscle memory skills with multiple key mappings, e.g., that overload that was mapped to your triangle button a moment ago is now something else - oops! Oh, and you'll also need to find a way to headcanon / accept the idea that, although your combat abilities are limited to a select few at any moment in time, they can be instantaneously reprogrammed.

- From what we've seen thus far, there may not be a mini-map that displays relative enemy locations - so, unless you can somehow continuously twirl in circles to constantly watch their arrival (spawning) and movements while fighting, you probably won't really know where they (or your squadmates) are. You'll know combat is over when your squadmates come out from behind cover and stand there waiting for you to continue.

- You won't be able to manage squadmate power use, so any tech or biotic explosions may be mostly on you. You'll just have to cross your fingers and hope they use the right powers at the right times to support your tactical / gameplay choices.  Will they also be restricted to swappable profiles - or have all of their abilities available?  Don't know yet.

- I've seen no indication of any ability to pause and/or pause-to-aim during battle. Just intense, frenetic combat.

I'll welcome more information, but none of this sounds good to me.

You can pause and access the radial menu for weapon and ammo choice, they shown that in December. I think pause to aim is gone though.

The swappable profiles isn't that different in how DA games work, where by pressing LT/RT or L2/R2 you access different abilities. You could map 6 in DAO-DA2 without accessing the radial menu with everyone and 8-9 in DAI. I think it'd have been better for PC to just have the various profiles's abilities hotkeyed to different keys, not the same three with a button switch.