I wish Bethesda would make next fallout like it used to be turn based RPG like Fallout 1, 2 and tactics and in a mean while they should be working on a spanking new engine because f**k me the current one is old a f**k, they are holding onto that engine like its a holy grail, its time Bethesda just let it go, dont get me wrong I still love you games.
PS upgrading an old engine is not making a new one, at least some people think that.

I think they are avoiding a new engine because they know a wide appeal to their games is easy modding capability. However I do not see this as an excuse seeing as the time they spend working on games could be used to finding something else viable. Yes having an engine that can render a ton of objects at once is hard but we are seeing bigger open worlds in others games manage a lot of objects now.

In terms of returning to the classic gameplay of Fallouts of old, I don't see that ever happening. Bethesda certainly enjoys their large profits and an ease of accessibility is part of that. I don't think the FPS aspect is a bad thing. New Vegas proved you can have en enriching RPG with this style of play.

After seeing where New Vegas headed i thought Fallout 4 will improve upon it and it will be even better than The Witcher 3. But everything changed when Beth released their post-apocaliptic shooter.

I've read through everyone's opinions, and I have to say these things.
Here's my jumbled semicoherent two cents.

If you want to go back to isometric Fallout, go play/mod Wasteland 2, because that is what it would look like.
Which is just fine, but I prefer open world type games these days, as my taste has changed over time.
FPS/RPG are not mutually exclusive, you can have both, but the series itself has changed hands a few times, and the series has changed a lot.
I remember playing Fallout 1, and dreaming of being able to do things I got to do in Fallout 3.
I liked that change.
I think the series has gone from pure rpg, to Action/Adventure with some rpg elements.
I would have been done with Fallout 3/New Vegas ages ago if not for the modding community, they've been able to make more things possible than I ever dreamed, and I have a feeling that same community will do their magic for Fallout 4 in time.

People can't be surprised at their favorite games being dumbed down though.
Here's an example, I love the Metal Gear series, but have you seen the trailer for Metal Gear Survive?
They've done this to the best games out there.
From Metroid to Resident Evil, no franchise is safe.
So, I take the comic industry approach to this.
Vote with your dollar.
If you don't like something, don't throw your money at it, it only encourages more of the same.
The people who create these things we love are going to follow their own hearts, and are going to do what they will, regardless of how we feel, but cash is king, and that seems to be the bottom line these days.
Oh, and write the company heads, they love letters.