D20 has always been a rather problematic and not well thought out system. The only reason its so common is because it was the first, thus is the go to example for people outside the hobby who just want to namedrop a PnP Rpg and because it has a large gaming company behind it while all competitors are smaller and often independent studios.
The D20 has such a high range of possible values that it drowns out any form of modifier, making mist actions basically just coin flips. Especially in 5E where the size of modifiers got limited.
First what alternative do you propose? I mean you can step down to the D6 system but I don't see the difference especially if you have to reduce the modifiers to make it workable and it reduces your ability to tweak the system in more subtle ways.
Having a larger die pool gives you a wider range of modifiers you can use to tweak the players difficulty settings. In Honor mode the D20 lets them push the proficiency mods down a notch slightly upping he challenge level without going overboard. Further tweaks are still possible even - in case people want an even higher challenge.
Finally, I think for many gamers it's about finding ways to improve your chances and that the gamble is the fun. If you always hit it wouldn't be fun at all, disaster and disappointment are part of the twists of luck.
