I never really have time to play many games tbh, just a few big titles which are open world/sandbox types, I used to play a lot years ago when most games were all linear with loading screens. That was partly due to hardware restrictions such as limited memory and cpu power until streaming from the CD became more popular allowing for larger worlds.
So for action/fps types is the trend to move away from the traditional linear type levels into open world games or not...
Short answer: yes.
Longer answer: You can find just about any kind of game out there these days. Even if we restrict it to the AAA space, You've got everything from The Last of Us to Crusader Kings 2. Action/FPS games such as Call of Duty are generally at the linear end of the spectrum, but even there you have GTA5, Saints Row 4, Far Cry 3, and so on. And even with Call of Duty you can argue that the multiplayer isn't very linear...
Plus, there are plenty of games that have an overall mostly-linear plot, but let the player advance it by doing missions in sandboxes: Deus Ex: Human Revolution, Dishonored, etc.
even with Call of Duty you can argue that the multiplayer isn't very linear...
It's very linear in my experience.
Spawn > Run down a corridor > get shot by someone I can't see.
It's really short, and I'm not sure about the replay value past a certain point 
I think the trend is more towards non-linear...but I'm biased. Some people like linear, simple worlds, others like to explore. Personally I like the ones that give you a choice like Splinter Cell...there are several paths to follow...with those sort of games you can choose to sneak by everyone or you can choose to kill your way through the level so long as you stash bodies neatly.
So for action/fps types is the trend to move away from the traditional linear type levels into open world games or not...
Nobody likes loading screens. Players hate waiting 30 seconds for the level to load. The dev team has slower builds and hate waiting 3+ minutes for the level to load. QA teams especially hate it when they spend a quarter of their day waiting for levels to load.
Since they are universally disliked, many games will try to get rid of them.
Many games will mask the loading by assorted methods. The slow elevator ride and the long hallway are both fairly common ways of doing level loads without a dedicated screen. They still take time but they don't feel quite as painful.
Streamed open worlds adds considerable complexity to the game engine. When it works well it tends to make life more pleasant for everyone. If you have the resources for it everyone will be happier, including everyone on the dev team and especially the QA team.
So while large continuously-streamed open worlds are increasingly popular, know that the costs are frequently measured in development-years. Everyone wants them, but they come with a fairly steep price.
