Nobody's opinion on Starfield is worthwhile. None of us know enough to form one.
Not even mine?! I think I know enough to form a pretty solid opinion.
It's a Bethesda game. I've played all those. I know the game engine, how the FPS part will feel. You can see in the trailer the trails from the bullets appear to be delayed. I'm pretty sure it will be the same as Fallout 3, 4, 76. Very standard, basic FPS action. No fancy movement stuff. I bet you can't even pull yourself up to head height walls.
So, if you consider what Bethsoft can do with the amount of time they've had, the size of the planets, etc. You're going to have an amount of hand-made content similar, at best, to F76 but spread out over 100 mostly empty planets. It would probably be in their interest to point the locations of interest out via quests or scanning from orbit. Maybe a treasure map or two.
We've seen the base building in Fallout4.
The single ship type first announced has become a modular ship which is an improvement but its still sub-par for a space game. If you compare to, say, Eve Online, Star Citizen, Elite Dangerous, X, or even No Mans Sky, which has lots of ships that are also modular.
I think the comparisons to NMS are the most valid because it would appear that Starfield has gone for the same casual control scheme for their ship combat where you turn to face the mouse cursor and can speed up or slow down. There were some nice damage effects but it looks like very simple combat compared to Elite Dangerous with its very detailed physics.
We can see the player walking around, zapping some iron ore from a wall, scanning some flora. You can do all of this in NMS, but NMS you can dig tunnels through the earth which has much more potential as you can find buried treasures, reveal underground cave systems, etc. (Though I haven't played enough NMS to see the digging live up to its full potential.)
The Starfield trailer was well made, though. I suspect they showed most of the quality locations in it.
As for the space exploration aspect, we know that you can't freely fly between planets. You can jump to a planet "instance" which is essentially a room with a planet in it. Then you can land on the planet.
I think, really, there's nothing ground breaking, genre defining, etc, going on here. It looks like there will be a decent story told by some voice acted NPCs with very bethesda looking faces with improved facial expressions in major discussions. Then you get some sub-par FPS gameplay, sub-par space sim.
Not to say the complete package wont be enjoyable, but it really doesn't look like anything special. I've been giving Star Citizen shit for a decade yet I'd happily submit to SC being a better looking game.
So, an opinion can be easily formed. They may be able to surprise me with the amount of interesting locations, whether they're generated or crafted, but I think it's very clear what the game is like. Pretty much looks like No Mans Sky only 10 free expansions behind in content.
I'm still looking forward to playing it, though.
edit: Oh, and I suppose I should mention how probable it is that people mod the shit out of it and improve the game a lot. As a Bethsoft title that could go without saying.