If a new Fallout game were to return back to its overhead turn-based RPG roots, it would really have to enhance and build upon what made Fallout 1 and 2 so good in the first place. Additionally, it would also need more interactivity, immersion, and focus in order to be really good. How it would be accomplished is the real challenge.
Considering all the advancements which have been made in the field of game development, I just wonder what could be done to push those advancements further. The last recent overhead game I've played which excelled in quality was Shadow Tactics: Blades of the Shogun, and that was merely an enhanced retread of tactical games like Commandos, Desperados, and Robin Hood: Legend of Sherwood. Shadow Tactics made those old games relevant again, and it succeeded on improving and expanding upon the mechanics of those game. Other modern continuations to classic overhead games I've seen were either marred by low budgets, unimpressive writing, or gameplay limitations. An overhead Fallout game would definitely need a higher budget and production values, but it also needs focus and well thought out design.
As for the first person RPG shooters Bethesda have done... The only one I've played through has been Morrowind, though I managed to play little bits of Arena, Daggerfall, and Fallout 3. While I am a fan of and have an enormous respect for Morrowind, and I like what I played of Arena and Daggerfall, the amount of grind you need to progress in those games is rather long. I'm more of a fan of the FPRPGs in the line of Deus Ex or System Shock 2, with explorable areas rather than massive unfocused worlds.
After playing through the original Fallout, I've noticed that the gameplay was far more focused, and the art and the design felt more satisfying. Consider Fallout's locations like Shady Sands, Junktown, or the Necropolis: they have the right mood and the right layout, and right amount of interactivity and quests. And the 3D sprites, textures, and talking head animations of Fallout 1+2 feel more to my taste than Fallout 3's graphics. I would long to see a 3D game which just used the 3D art style of Fallout 1+2, and just enhance them a little. Could you imagine character models in a Fallout FPS which had the same depths and expressions of the Vault Overseer from Fallout 1's intro? It would probably be pretty expensive nowadays to execute. Even though Fallout 1's and 2's cutscenes and talking head animations would be considered antiquated, I've barely seen 3D games nowadays which could replicate the detail and graphics of those animations.
When it comes to my preferences for a Fallout first person RPG shooter, I'm more partial to a combination of old and new. I'd like to see an installment which combines what worked in Fallout 1+2 with other classic first person games such as Ultima Underworld, System Shock 2, Strife, and Thief. If it were possible, I'd just like to see the graphics, sprites, textures, and art of Fallout 1+2 rendered into a 2.5D engine. I'd long to see the Necropolis and its ghouls replicated in such an engine just to see if it could be done.
The funny thing is that awhile back on You Tube, someone made a joke video which speculated what would happen if Interplay turned Fallout into an FPS before Bethesda did, and just showed gameplay footage of Redneck Rampage in black and white (because Interplay published that game). Considering that RR used 3D sprites and textures, maybe it could've replicated Fallout's style. That would've been a crazy thought. How would a post-apocalyptic RPG version of Redneck Rampage work out?
The only other FPS I think could've been a good template for a first person Fallout would be the original Deus Ex. Just replace Deus Ex's skills and augmentations with Fallout's skills and perks, allow your character to earn skillpoints after winning battles against foes, follow Fallout's mission structure, and implement Fallout's day system. Other possibilities would be to make more interactive and advanced modifications for Fallout 3+4 and New Vegas which better represent what fans want.
Other than my suggestions and ideas, I have no idea which approach would be best, or what would be the best way to execute such approaches. I only hope the really experienced fans will someday reach positions of power in the game industry, and be able to execute the Fallout games they deserve.
