One of the main changes made for Trion's adaptation of the Ancient Devil God Scramble is that each channel supported up to only 120 players. Once 80 total players were in a channel, the 5 minute countdown would begin. Once that timer expired, players were immediately divided into teams of offense and defense. Base siege turret altars were added in the 3 zones just outside the barricades providing a capture and control element since they served as respawn points for the side that kept control of them in addition to removing the lightning from those small towers near the barricades.
Unlike the Scramble siege, these teams are not based on guild or guild alliances. The field bosses were only used to acquire buffs and after they were defeated, chests were spawned at the boss, just outside the barricades, and in the central altar area where the tower is (this particular aspect has led to some major dysfunction in Stormfront Wars which will be detailed on a separate page). The central altar also does not spawn Cycloid; the main objective of Stormfront War is to defeat the Guardian Tower in the shortest amount of time possible once any of the three barricades have been breached. A final reward was also given to a player on the winning team; a Legacy Chest that guarantees 10 gold bullion (each bullion giving 100 gold) as well as a chance for a heroic devilian weapon to drop (in weighted order: grand -> rare -> heroic).
Contrary to the patch notes which stated that the "winner" of the Legacy Chest is given to the player with the highest contribution (true in the original Scramble design where core designs relied on last hit mechanics), it is not determined solely based on being top contributor or top 5 class contributor for this modified version. If that were the case, the best Devilian geared characters would always be winning the reward. So while those two factors part do play a role in the calculation, it also includes a number of other things that aren't displayed in the breakdown of what constitutes contribution (some of the main ones include PVP assists and kills, capturing siege turrets, controlling/defending the siege turrets, damaging the barricades, destroying the barricades, engaging field bosses, acquiring the last hit on that field boss, damaging the guard tower, acquiring the last hit on the guard tower).
Trion's version also has a bug where it is possible for more than one player to receive a Legacy Chest (not announced system wide but you will receive it in the mailed rewards). AFAIK, this issue has never been resolved as besides being the announced "winner" of the chest, I have received it in the mail several other times.
This siege event by extension utilizes MOBA game play elements Ginno developers used in the Battleground design. Zerging does not always translate into completing the objectives in the shortest amount of time (dependent on how many players are contributing and actually not AFKing). That is one hint that will be offered as to how to increase the chances of acquiring the legacy chest (the only good thing from that box anyway are the gold bullions).
Like so many things in the original design of this game though, best geared does not always equate to being the top "winner" and that is true for this event. Having either gold or silver crown hovering over the top of your character throughout the siege might have made sense in the Scramble version until full engagement between siegers and defenders happened once the barricades were breached. In Stormfront Wars, those two crowns are like annoying beacons that gives like minded players easy targets to focus on especially towards the ending of the event.
There is a "strength in numbers" aspect that is prevalent in Devilian form play which made sense with the original Scramble event where factions were based on guilds and guild alliances.
Alliances mattered in core Devilian including IHG capture zones, field boss scrambles (devil hunts), and this siege battle. The numerous game design changes made to the Trion version of the game (including the removal of Devilian form battleground PVP) has negated the alliance portion of guilds. Stormfront Wars for example has no mechanism for allowing each side to communicate just amongst their own faction (besides the raid leader notices) since teams are not composed in the same way (guild and guild alliances). The change to the artifact system (utilizing gems as enchanting material) and removal of the failure mechanic for upgrading gems negated the meaning of gems drops from captured IHG zones. This is why capture zones aren't as meaningful in Trion's version of the game (and Ginno flatly turned down the request to increase the gem stepping levels that drop in the IHG's).
Additionally, some of the last hit based mechanics when it comes to stealing contribution still plays a role in this siege since it is something that Bluehole Ginno probably forgot to remove (the last hit mechanic and stealing of contribution was removed from co-op and devil hunt bosses well before the level cap was raised to 54).