I'm not disappointed that it's open-world. It's a Bethesda game. Of course, it's open-world. That's what Bethesda does best.
What puts me off is that the open-world aspects do not seem well executed. The appeal of Bethesda open worlds (at least for me) was wandering anywhere, in the natural environment, in any direction, and finding something interesting, weird, or surprising. Apparently, that sort of open-world exploration does not exist here. You are teleporting everywhere, and the "exploration" is mostly of barren, featureless, drab planets, where nothing is to be found, apart from invisible walls and cut and paste buildings. In other words, one of the main charms of a Bethesda game -- the free and rewarding exploration of that open-world -- is missing here.