Being an older player and gaining advantages just because of time without having to do any other effort for it besides waiting: 
The other choice is very OOC, regardless of the seemingly logical arguments from its defenders. I would be surprised to see an alt I almost never play to become famous among NPCs instead of a common individual.
For those insisting on this "old is better" talk, remember that M$ is much younger than IBM and still grew much faster than it. Let's make one deal: older player characters don't get any patronizing, just the acknowledgement of the other PCs(only if they are commonly online), an new PCs have harder begginings already(0 tria and no items).
Recognition from NPCs isn't something that I had proposed. That's part of UTM's idea.
That said, I still see it based on soley on time as the only way to realize the intention of the stat while avoiding both favoritism and exploitation.
Also based not on time existed but existed in-game = online...
Exploitable. People would just leave their characters online all the time. There are already a few people who became well known for this because there was a webpage which showed the stats for who had the highest stats, who was online the most, who had the most advisor points, etc. So people left their characters online all the time without being physically present at their computer so that they could have bragging rights.
Listen, this can be done in different ways but let's not forget the fundamental intention of the wish: A way to distinguish old characters from new characters such that old characters will always have certain, if small advantages over new characters - even if the new characters are power levelled and rich.
It might be a slight boost to stats. It might mean access to certain items and quests. It might mean the ability to equip certain items in the same way that certain items require a certain level of strength or intelligence to equip.
Will it be unrealistic for certain characters? Yes, and it won't matter because such characters won't be particularly active. Further, this stat will be largely transparent and invisible so you won't even notice it in most cases - especially if the character in question hasn't taken advantage of the benefits available to him or her.
Why can't it be affected by in game activities? Because no matter how you do it, it will open the door to powerlevelling and exploitation, and it will go against the intention of the wish. Because of the reason for the stat to exist, there's no reason for the stat to be based on in game activities.
Does it have to be called Heroism? No. Does it have to be called legendary status? No. Does it have to have ANYTHING to do with reputation or how well known you are? No. Does it have to be terribly in character and realistic? No. Call it "
aura" for all I care. Call it "
the force". Call it "
we're going to insert a creative name for this stat sometime in the future but for now just think of it as a sort of abstract principle that is mostly representational in nature". It's a means to an end.
