With seriousness, though?
If the gameplay is essentially ME3:MP's but you can holster/un-holster your weapon whenever and explore about like in ME1? I'd be okay with this.
. . .just don't give us planets that are a long pathway to the end. I just did Liara's recruit mission in ME1 and just- UUUUUUUUUUUUUUUUUUUUUGH it was as boring as she is! Virmire wasn't that much better either despite how pleasant it looked, whereas I enjoyed maps like Luna and Asteroid X57 as I could explore a large map. Not much on them mind, but that's where larger, more varied world in ME:A would come in: things to find, explore, shoot, talk to, yadda yadda. I did enjoy ME1's Citadel though, even if I got tired of walking around and just used the Transit stations.
Yeah as far as ME1 Citadel and Noveria were done well in my opinion. But i hated the blank planets with nothing on them, except random stuff to collect and the same repeating map with enemies. I like missions where you are given 3 way to fix it. ME2 scanning wasn't terrible but I ME1 scan the planet when you find it, no more unless a mission there, was better, but I hated chasing down minerals on the planet proper.
ME2 didn't really have open world, and I do like 3-4 places that have major plot arcs, and you building a bigger story with quite a few minor ones on the way. Major Quests making the stories, minor quests doing the themes, and a few different ways to do them to build variety.
Exploration in ME1 (the only ME game to have it) was bland and in my opinion the worst part of ME1, the idea of going through it again for another playthrough always makes me hesitate. Knowing they will focus on exploration makes me hesitate because I don't personally like exploration in games, and I recognize that prejudice.