Yes, by doing very foolish things in altering a characters look and/or storyline. But it also depends on the character and to what degree they are "ruined". For example, Sub-Zero's dragon amulet enhances his powers but makes him an older man... and he supposedly was overjoyed to obtain this item after wining a dramatic battle against Sektor?

Sounds kinda silly to me. There was no need to have his amulet bring any drawbacks to the table. He earned it after fighting bravely and his reward has drawbacks? Odd twist for one of MK's greatest characters. I mean, did Scorpion lose anything from gaining even more power by chillin in the Neather Realm?

No, he didn't.

The unmasked Sub outfit was awesome and he would have been my favorite in MK:DA if only he didn't look like he was 60. Many sub fans (who haven't deluded themselves into liking the "old man" story arch because he has always been their favorite, and they had to) would agree with me.

Did this kill the character? No way, Subs as popular as ever. But, would it be equally silly if Boon made Scorpion slowly rotting away when he's not in the Neather Realm (looking old and tired), after he finally kills Quan Chi? Yep, pretty much in my opinion.

The majority of fans hands down loved Subs new duds, but hated Sub-Zero being made to look older. Why did the decision to make Sub-Zero grandpa over night ever leave the board room?

Good question. Why was Scorp actually left out of an MK? Another good question, and there are plenty more where both of those came from.

Updating and modifying well liked characters is the hardest thing. Sometimes it works really well, and they get a whole new level of popularity, like someone said Sub Zero. I think this could also happen with Ermac and Smoke, now that they're no longer pallete swaps. Other times, like Jax in MKDA, it fails and puts people off.

It's difficult to get the right balance of having popular characters evolve, without getting it wrong, but it has to be done. Or they'll end up like Liu Kang, who got very stale after MK2, and only now they're trying something new with him.