Vanilla Myst had two major issues, and with this game one of them has been fixed.
The first issue is the nature of the puzzles themselves. Although they are deliciously challenging at times, there is quite a bit of 'find solution, write down solution, walk across map, apply solution'. This will never be fixed, but it certainly doesn't make the game anything less than spectacular.
The other issue, and by far the most severe issue, was how old the damn game was. Assuming you could even get it to start, you had to find a legacy version of Quicktime and were playing the game in 320x240 which some monitors don't even support anymore. A side effect of it's age was the graphics quality being garbage. Usually I can overlook graphics in a well-crafted game, but when a game relies so heavily on immersion and observation, and is prerendered with zero fluidity of movement, having visuals as poor as Myst's simply detracts from the overall experience.
It is for these two reasons that I had trouble getting people into the Myst series. Riven, which is quite possibly the greatest game of all time, relies on players having experienced Myst's universe and story. So you were left with two choices: Wrestle Myst into submission and persuade yourself to beat it, where the only redeeming factor at this point is it's imperfect puzzles, or play the also-ugly and also-buggy realMyst.
With the release of realMyst Masterpiece, I can finally say that Myst is fixed. While the graphics aren't quite perfect, and there are still a few cosmetic bugs, and the puzzles are the same puzzles as ever, I feel like this game actually deserves to be Riven's prequel.
In short, there is no longer any reason why you should not play through realMyst Masterpiece and then play Riven.