well, one could argue that every graphic RPG ever made is simplistic and shallow compared to a well crafted MuD (like Gemstone 3), and every MuD is shallow and simplistic to one of the more complete tabletop rulesets, like, say Rolemaster.
No, not every game needs to be simplistic, but every game needs to generate enough revenue to pay for it's development, and that's no easy feat for complex games, especially complex games in what is effectively a niche genre.
This is true to an extent, I think. The most complex rules I've played with have been on a tabletop, and the most complelling, deep and emergent roleplaying experiences I've had have been on MUDs (well, MUSHes if you wanted to get specific, but they're all essentially the same.) While the prettiest, and I guess you could say immersive, times I've had were on a computer.
I don't think it should have to be that way, though. I remember getting my first computer back in the day (a 386 if memory serves) and thinking of all the potential this thing had. In my mind, what I would like to see as an emphasis for CRPGs is a way to combine all of the strengths of these various types.
A computer can handle a much more in-depth system than anything you can come up with for a tabletop ruleset, which has to be simple enough for people to quickly figure out without a scientific calculator and random number generator (though I've played games like that - and it takes
forever.) And graphics shouldn't have to be a detriment to some good, old-fashioned roleplaying when dealing with other people. (I'm not a huge fan on online games these days, but the MMO genre has taken a turn towards cooperative dungeon-crawling more than it is acting out a living, breathing character - though yes that the opportunity is there in any MMO and players of that sort is hard to come by points to a lack of interest in that type of gaming.) I remember acting out my character just sitting in a bar when I was in my MUSH days - all the plot-lines were developed by fellow characters and entirely emergent for the most part. The addition of graphics could easily serve as just another tool in the arsenal, as opposed to taking away from that emphasis.
It is a sad fact (I think) that the reason we don't see games taking on this challenge these days points to a lack of market interest. But we all have our own metric for critiquing a videogame, and my own standards fall along the lines I've dilineated above. I try to keep the game's budget priorities out of my considerations in what I feel are faults in the game. Because they have reasons for doing things the way they do, and not making their priorities akin to my priorities doesn't mean that I agree with that choice.
I'd still like to feel that a high quality game is going to garner some interest in the same way that a well written movie will be successful. You have to keep your target audience in mind, of course - but you still have to provide quality to that audience. I can throw all the money I want at special effects in a movie - but if it doesn't have a compelling plot and sympathetic characters - it's not going to do as well. You can have a big-budget action movie with a compelling story to tell - I don't see how that isn't possible in a videogame.