I think that you're used to 'RP extreme' MUDs ("M*s", due to the whole MUD/MUSH/MUCK/whatever naming convention), from what you've written. But I can see you don't have the same idea about immersion as I do. In the "The pictures are better on radio" kind of way. So I won't try and dissuade you.
Where I'm most regularly seen, I admit it's not an overly RPing MUD (you can, or you can 'play the game'). Typing "sit contemplatively" will get be emoted as "
Starver sits contemplating" and observable as "
Starver is here, sitting contemplatively" (only with my MUD moniker in place of "
Starver", obviously). It is of course an a partially 'empty' description, and "sit cotnemplatively" will see my character "...sitting cotnemplatively" just as easily, without regard for any mechanical interpretation of the sense of the description besides the fact that I am, indeed, sitting.
And if you're after actual graphics, then (largely, and I know there's MUDs with capabilities beyond the mere telnetesque textual/ASCII-map aspects), obviously it's not for you. But if I care to (and am part of the player-run community of 'archictects' and given domain over the area concerned) I get all the tools I need to change "This is Random Street, <insert sunlight and weather information here" into "This part of Random Street is decorated with many coloured banners and streamers, redolent of the culture the local immigrant population has imported with them", or whatever needs to be done for that locale. I could even be entrusted to add extra doorways (i.e. exits, visible or hidden), decorate out extra rooms behind those exits, install an interactive NPC or two, items to pick up or use in place, events to occur and the like... It's not drag'n'drop... but, on the other hand, it's
not drag'n'drop. Much better than that. If you can get beyond the text/keyboard nature (as opposed to the largely image/KB+mouse interactions of a 'modern' MMORPG), there's a lot more possibility in there.
But it's not for everyone. And neither is each
MUD for everyone. There are doubtless some where Broneys rule, while in others its an S&M(&muchmoreS&muchmoreM) fantasy locale. Some take existing fictional universes, others are totally self-created/evolved. I've seen ones with landscape and room changes very much Minecrafty (geographically, every 'room' is ironclad set in stone insofar as which exits there might be and connection to the next areas, but just about every feature of the room is modifiable by the players according to very limited rules so that palaces can be 'carved' out of the informational ether), ones which are only ever alterable (and
that very rarely) by The Person Who Has The Server In His Bedroom/Office, everyone else just gets to play Capture The Flag or whatever other entertainments He has arranged, and ones where a heavily player-community-led architectural corps refine, improve and develop the already rich environment, on the whole, with the only real Super-Administration tasks left to the privileged few (who, themselves, are probably now overwhelming coming from the past generation or two or three of past 'casual players' who became fixtures, and perhaps one of whom took on the hosting of the MUD after the original Founder decided to move on), such as decisions on how to tweak the stats/skills systems, introduce whole new swathes of the planet heretofore left sealed behind virtual "Under construction" hoardings, etc, etc...
And 'play' within the MUD could be entirely freeform emote-based, or very nearly every keyboard input is skill-checked and calculated and cogitated over by the system, according to the bounds so given. Somewhere in-between might lie your "Action game" and all else that you desire.
For someone like me, with less of an art in... well, art... than in descriptive language (as most people already know, it's often hard to stop me!), I could see myself setting up the structure of a MUD much easier than I could develop a Skyrim[1]-like world. And with a whole lot more possibilities and freedom, as long as nobody is looking for pretty pictures to accompany their journey.
Got some pretty solid ideas set down about how it would work. Could even integrate into a WorldGen map, to give an authentic landscape (in text form, but there's nothing to say how as to how that cannot include ANSI-like output to make it similar to Adventure Mode). It'd not be so much "multiplayer DF", of course, and I'm afraid it'd probably be a little Minecrafty in all the areas where DF is unsuitable for multiplayering. But as a mental exercise I liked to think I'd nailed some of the difficulties. Which are drastically lessened if you actually restrict it to a Fortress Embark area, instead of global, use a suitably generated (or ripped from savegame) fortress, then allow each MUDding character to be a migrant, newly entered onto the map, to decide on how they can best make themselves useful in whatever role, but released from the Armok-led "a wall must be built" directives and instead making those decisions themselves. Or just wandering around and killing the local wildlife. Or more. The "or more" is the bit I'm sticking on, at the moment. Transient characters, persistent world with non-permanent residents, a bit like the plans for running a DF-like settlement in a Minecraft world, that I remember being talked about a while back. Whether "Goblin"/"Kobold" players on that were only to attack when there were regular players 'manning' the fort, otherwise it would just be wall destruction and landscape despoiling. As such, there's a lot more to be considered. But I reckon a decent homage could be done, regardless.
[1] Saw that for the first time, today. XBox version. Mostly I was wondering how much of the landscape was procedural, and how much was artist-led. Obviously artists created the "clump of mushrooms" object-like, but then did they get deliberately painted into particular spots just off the path, and stored as such on the map, or was there always going to be a "clump of mushrooms", or something similar, in that spot, persistent across the many occasions that the character might mover that way by dint of the XYZ-coordinates and the like saying "put plants there, type mushroom, orientation such-and-such-degrees from north", sort of thing. Anyway, idle thoughts, from someone who through lack of personal artistic creativity has gone down the route of almost entirely procedural 'flavour dumping' in various never-seen-the-light-of-day personal projects along those lines. And the artwork was often terrible... And/or itself procedurally-derived. But then some of this dates back to the early '80s, when not much was expected of computer displays. Or at least far, far less was demanded...