The problem is that at low levels (and for anyone that doesn't have expertise) that DC 15 is going to fail more often than not, especially at low levels. There are times I just want to have players stealth past a dozing guard with an effective passive perception of 5 or less. It should be automatic from anyone with any skill at all, and even fairly easy for anyone else.Ive always been fond of rolling against the environment for stealth, with failure triggering perception attempts, and critical failures inducing an immediate position reveal.
The two stage process best mimics how stealth tends to play out in video games. If you don't stealth properly that doesn't always mean you're found out; enemies are usually alerted to something and then they go searching. Your stealth check in this case would basically either have to fail twice, or fail very very very hard.
The question then becomes how to determine where the line is for critically failing. I think its better for it to start close to the DC and move farther out as you gain experience, but as a general rule, 10 or more short of the DC works. (Ie, PF Crits)
Either way, you get room to recover, and a clearly defined opportunity to potentially try abilities or other Skills to get around the failure, rather than trying to beat the DM to adjudicating.
If these are the only rules I have to follow, I can't follow the rules at all when sneaking past a drunken soldier and an alert ancient red dragon and have the scenario matter. We're always going to hit that DC 15 check.
Yes, video games handle this stuff differently. Because they're video games and the code has to be simple and binary. DMs can handle a lot more ambiguity and alternatives. Giving DMs latitude on things like stealth can really help set the tone for a game. I think different groups potentially running stealth differently is a strength of the game.
Oh, and the other issues I listed above still apply.