D&D has always been more than a set of mechanics. The edition wars are really over what set of those mechanics on likes. So why does the legacy of even matter? As a general rule I tend to think of something iconic in D&D as where it was first introduced to the game. Drow for example to me should have something like 50%+2% magic resistance and be able to levitate, use faerie fire and have weapons and armor that disintegrate in the sun. This applies to things like 4th ed as well. Dragonborn for example should probably have a bonus to strength or charisma, breath some sort of elemental weapon and look like a Dragon man. A little change is ok though so I would not be surprised to see the bloodied condition go. A little change is also something like the Ranger no longer required to be good aligned in 3rd ed.
The further one moves from something being iconic the less the IP means to the consumer who liked it in the first place. Sometimes things are just plain ol bad. Original Star Wars movies compared to The Phantom Menace. To many changes and if something is to different you just give up on the IP regardless of how good or bad it is. Now I'm not going to throw my toys over a Drow being a little different than what they were in the past but the most iconic Drow to me are more or less the ones from 1st edition AD&D adventures and the Fiend Folio. Note I never ran AD&D 1st ed and I only got to play it briefly in the 90's with some grognards. I do not care if someone reskins Drow on a specific setting of course so something like Eberron Drow are fine or the Driders of Golarion. If something is done well I actually prefer it over the original. Halflings for a example a little boring and out right Tolkien rip offs. I prefer Darksun and Eberron halfling over the default halfling but if I was designing D&D I would use the default halflings and if I did consider a change to them I would put up a poll requiring an absolute majority (75%+ and probably more like 90%). Or I might even use several polls.
1. Are halflings boring y/n. If enough people say yes.
2. Do you want them replaced y/n. If enough people say yes
3. What do you think of the following options a, b,c.
That is for major changes. I do not expect the designers to design the ranger like it was in 1977 for example but it should at least resemble the concept- wilderness warrior, casts spells (level 1,4,8 whatever), and it has some form of favored enemy ability. I would not bother polling something like that as that is part of the designers job. You will not please everyone all of the time. A major change where you would want polling would be something like "Should D&D go classless". Major change like that can really blow up in your face. You would not want to design everything democratically though s some hard decision will need to be made. "Hey guys do you want free candy" except the candy is not free- someone pays for it.
So what if you hate tradition and the classic D&Disms that some of us do care about? That is up to you but words have power and by that I do not mean the Clerical words of power or the power word series of spells. Gygax, Elmore, Mentzer, Monte Cook, Heinsoo and Tweet if you are referring to 13th age. These names mean something and it doesn't matter if you like them or not. Names can also have negative connotations as well even in D&D. Lorraine Williams is a good example of that as you will not find that many fans of her anywhere despite she probably did save D&D for a few more years before WoTC picked it up. Then again some will argue that what was saved was not worth saving so it can go both ways.
Legacy matters, mechanics not so much. They change every edition.
Fear is the Mind Killer