That's actually one of the things I like about open world experiences, specifically RPGs. That you can go anywhere you want, and you might stumble upon a place where enemies are way too strong for you. Then that gives you a choice. Do you explore and try to avoid the enemies or do you wait until you're stronger and come back later? I think that gives you a sense of progression as well. That you can't go everywhere in the world right away. I mean, you can if you want, but you'll likely be killed. I actually prefer open world games to have areas you aren't supposed to explore right away, it gives you a goal to move toward. "I'm gonna level up and come back to this area and fuck up these SOBs that are kicking my ass right now." But I've played games that are like that and I'll wander around in tougher areas and avoid fighting and was able to pull it off, it's kind of exhilarating, but technically the option is still open to you if you wanna give it a go.
Having everywhere completely open to you from the beginning though isn't fun for me. I like having areas that I have to progress toward, being able to literally go anywhere with no trouble really takes the fun of exploration and suspense away from me.