Long story short, you are probably right that it's not a seamless open world entirely, since it's an MMO Shooter with RPG-lite features. But what's the problem?
No problem. Making observations. I just don't enjoy fluffy demonstrations, which coincides with misleading people for the sake of hype. I'd like to see real gameplay and I'll determine further. So far I've found being highly skeptical of things like this serves well in the end, and if not, I'll be pleasantly surprised.
I want real gameplay. Not a demonstration of how pretty the little 3D map works and some [Insert name here] Skill icons. The AI was absolutely brain-dead, there was the magic healing from half a football field away.. [I won't go into how absolutely lame and stupid this will be if there is 'open world PvP' or whatever it's even going for with the instances, i.e. 'look, I'm on a roof and my whole party can be healed with my telekinesis!']
I guess it has cover mechanics and a tablet drone? Neither of which particularly scream 'Buy now!' to me.
Speculation here, so don't expect this.
Note that, in the demo, it did show the telepathealing. I expect, if they follow classic GR:FS style boosts, that player would have actually
dropped a medkit with a certain number of uses and the team would have to
rush between cover to get to it. The cover mechanics are gloriously sound if they keep them the same, from rushing (which, confuses the hell out of the AI, it never was all that smart.) between cover (Suicidal versus players if you're running a path even close to their direction), limited health that, unfortunately, does regen unless you hit critical, cover jumping, cover where if you're getting shot at with a big enough gun you'll duck and not be able to see over the cover, looking around corners, firing around corners, stance changing aim, cover and stance changing accuracy, three types of aim... (not aiming, as in hipfiring- you won't hit shit, aiming, which gives you a tighter accuracy circle without restricting your sight, you'll still waste some ammo here, and aiming down sight, the most useful but least mobile, really only "safe" if you happen to be prone and a good distance away in a spot your enemy hasn't seen you in yet.)
If they were to keep the base engine the EXACT same, plus or minus some balance tweaks and general updates, and focus most of their development time on the AI, it could be amazing.