Will there be Fin Gleam in ESO? I sure would get a laugh if it was.

If you know what Fin Gleam is, well done.
If don't know, it is the very definition of 'Reward for exploration'.

If it will, it will probably be 'hidden' in a level 40 area, so you'll have zero chance of acquiring it at your early levels.

You have to realize that this is an MMORPG that ties area progression to the main quest (at least in the tutorial area).

Also if there's an easily accessible OP item hidden somewhere in the world, soon everyone will know about it because of the nature of the game.

I'd rather have some interesting little stories like notes, corpses, some ruins as the reward of exploration.

True to all of that.