So which is it? Is there only 1 reward for the top attacker or is there multiple rewards for the champ? I'm not going to go on and on but top attacker is a bad system as it leads to the same person getting the reward every time. One day I hope to see that concept identified as bad.
The new system is tracking the players working the spawn. Once you've reached a certain threshold, you are automatically added to the list of people who will have a chance of receiving the rare item. The person who worked the spawn the most will have a very slightly higher chance of getting it. So technically, if you are on the list, you do not necessarily have to kill the champ to receive the item, but it would increase your chances if you did. You however must be on the subserver or you are removed from the list. If you are dead, the item could drop on your corpse (not on your ghost).
If none of the people on the list are present when the champ dies, then a random player among those who helped killed the champ will receive the reward.
When killing the boss, the breakdown for the rewards is as follows:
10% chance of no reward
10% chance of the boss specific reward
45% chance of a decorative reward
35% chance of a shared reward.
For example, if you're doing Oaks:
10% no reward
10% chance at Orc Chieftain Helm
45% chance of either the wind spirit or one of the 4 animated water tiles
35% chance of one of 6 Replicas (Survival Knife, Djinny Ring, Lt. Sash, Samaritan Robe, Detective Boots or Knowledge Robe).
Note that Oaks has the most shared replicas. Most other champs have 3 or 4.
As far as people farming the Tram ruleset spawns, keep in mind that there is a timer before the altar is self-reactivated. You will probably remember the days of ToT when we were all sitting around waiting for the spawn to begin again.
The SoTs are totally independent of the boss. Whenever you work the spawn you get a chance at receiving a 105 or a SoT scroll. In Trammel, you will only get the SoT, in Felucca you will get one or the other.