I personally like the idea of offering Raid-related prizes, but I was thinking something different from Badges. Aside from the obvious "lawl, badges for Badges" confusion, I don't like the idea of offering a prize that I'd need to change with every expansion. Also, it'd be awfully generic. Therefore, I would like to introduce you to...
Heirlooms!
In the universe of Warcraft (to which the Raid Zone is inspired, if you hadn't guessed it already),
heirlooms are special items whose stats scale with your level. So, if you wear them at level 5, their stats will be as low as your typical lvl 5 item. But as your level grows up, your heirloom's stats will improve accordingly. By the time you reach level 70 or 80, your heirloom will have stats on par with any rare item you could obtain from mobs of your level.
So, how would Heirlooms look like in ASB Raid Zone? My current idea (not final ofc, we're still in a discussion) would be the following. Assuming you have never been in a raid before (or you have been but you lost, hue), your Heirloom would have stats equal to an iLvl 3 artifact - basically, just a tad better than a normal item. But as soon as you defeat a raid (or if you already did before getting your hands on the Heirloom - it's retroactive), the Heirloom's stats would increase accordingly.
Let us see an example of a Heirloom item. This Heirloom would be tuned for healers in general.
Inherited Light's Hammer: Raises the STAB bonus of the holder's attacks by 3. Increases the healing and absorption done by the holder's direct heals and absorption effects by 1.
(Note: "Absorption effects" is basically here to cover the newly introduced Bubble Shield)
These would be the stats if the user in question has never won any raids before. Now, let's suppose he has won a raid from the Stormrage Mountain subzone (the "Vanilla" ASB Raid Zone, so to speak) on any difficulty. This would cause the Heirloom's stats to raise to those of a iLvl 4 item.
Inherited Light's Hammer: Raises the STAB bonus of the holder's attacks by 4. Increases the healing and absorption done by the holder's direct heals and absorption effects by 2.
Now, let's suppose this same guy defeats a raid from Isle of Lost Relics (the first expansion), again on any difficulty (this includes Raikou/Entei/Suicune too). This would increase the heirloom's stats further, bringing it to an iLvl of 5:
Inherited Light's Hammer: Raises the STAB bonus of the holder's attacks by 5. Increases the healing and absorption done by the holder's direct heals and absorption effects by 2, while reducing the energy cost of these moves by 1.
Finally, should the user manage to defeat a raid from Hour of Twilight, the Heirloom's stats will reach their current maximum, becoming those of an artifact of iLvl 7:
Inherited Light's Hammer: Raises the STAB bonus of the holder's attacks by 7. Increases the healing and absorption done by the holder's direct heals and absorption effects by 3, while reducing the energy cost of these moves by 1.
Should I release a new expansion, a new "tier level" would be unlockable.
Ideally there would be at least one Heirloom for physical attackers, one for special attackers, one for healers (not necessarily the one in the example), one for tanks, one for supporters in general (who don't have to be healers), and so on - depending on how many prizes on the "leaderboard" we deem necessary.