I actually prefer if levels aren't visible, so the game feels longer.
For me, it works strictly backwards. For example, the first time I completed Leon's campaign in 9 or 10 hours, because I played slowly and tried to explore everything. However, the game encourages you to play quickly and not pay attention to such things, because they really have poor quality. If the game has some touches, they are shown as clearly as possible so that the player notices it without breaking the pace.
The remake of the third game is also short. Like Leon's campaign, people complete it in 5 or 6 hours. However, I completed it in over 25 hours because the game has a good environment. I was glad to find a mention of Albert Lester and a mention of White Umbrella, which was very well hidden.
But I understand that this is an incorrect comparison. Resident Evil 6 has not one campaign, but four. Moreover, both games are still designed differently.
I am sure that the poor quality of the environment is due to the design of the game and the amount of content. If the game is not focused on the environment and is very large, you are unlikely to want to spend time on something that is not a priority. This is not even laziness, but just optimization of production. And I just want to say that this does not correspond to my personal preferences.
Even in classic RE games, all the progress can be segmented into levels or chapters, it's just you don't see them.
It's true. Even Resident Evil 7 is literally divided into chapters that have their own titles. However, this is not the same, because the level design of classic games is close to the open world in the sense that you can freely move around locations and choose routes. Games in the series like Resident Evil 5 are more like a linear chain of arenas connected by corridors, along which you need to move, but only move forward. This makes sense, since these games are action-focused, so they're not designed in such a way that you need to do backtracking and think about whether it's worth fighting the enemy at all. You just shoot and punch them in the face, lol. And the game encourages you for this with resources, currency or points, motivating you to kill more enemies.
Speaking of Resident Evil 6, this game has a very good combat system and a fast pace. However, locations sometimes seem dark, poorly lit, and claustrophobic. This is something I particularly felt about Chris's campaign: running fast through the narrow corridors sometimes made me feel uncomfortable. And the cover system really sucks. It seems to me that this is why The Mercenaries reveal the combat system better, since they give you an open arena and do not limit your movements. I feel that the locations of the two previous games are better designed and have a great pace for this kind of design. And I also really like the environmental storytelling in Resident Evil 5. Especially the Ndipaya Kingdom.
But, to be honest, I'm not the best shooter (I genuinely hate the shooting chapters in Resident Evil 5 and Revelations, when you need to shoot and someone else controls the transport, and these games still take into account the percentage of shooting accuracy) and I play very few action games. I'm more of a person who likes to meditatively explore locations, search for items, solve puzzles, and read files. I even grew up playing games like Necronomicon: The Dawning of Darkness. If you've played this game, I think you'll understand perfectly why I prefer the remake of the first game and Resident Evil 7 more than any other approach to the franchise.