I don't think it's going to suck, I just think it's got a tough hill to climb for a few reasons:
It's a space RPG with shooting, exploration, and base building-- that puts it directly against very established similar games like Destiny and No Mans Sky. While Destiny isn't the same genre, a shooter RPG set in space will inevitably draw comparisons. All the updates to No Man's Sky over the years has basically turned it into a Bethesda-lite game, just with a very meager 'story' behind it. Guaranteed these will be two of the primary games its compared to, along with Elder Scrolls and Fallout, of course.
Its audience is squished compared to Bethesda's past mega-successes. Skyrim has been on every platform except the Wii U. X360, PS3, XBO, PS4, Switch, XBSX|S, PS5 and, of course, PC (and Alexa!). Starfield is going to only be on current gen Xbox consoles and PC. In addition, sales are going to be squished because it will be day one on Game Pass, so the only two places where it will be playable, people will be able to play it for a pittance of a subscription fee rather than buying it outright. That's great for player metrics but tanking sales is bad for overall longevity. I think cutting out the largest console market is going to come back to bite Microsoft in the ass, even if the game is great.
A lot of Bethesda fans want Elder Scrolls 6 rather than Space Fallout/Skyrim. The grumbling about TES6 still not being in full development grows each passing month. If Starfield isn't absolutely amazing, I expect to see quite a few bitter "We didn't get Elder Scrolls 6 because of this?" posts on social media.