Love, Love, LOVE this idea! So, going to steal a few of the aforementioned ideas, add some of my own and throw in some pros/cons along the way 
The ‘elements of a titan’ aspect is very interesting. Each area could be a different strength like Very Easy, Easy, etc. This would allow smaller alliances/players the ability to join in on a * of titan that may typically be out of their range. SG currently uses those types of rating on events, so I’m thinking something similar.
This might work better as an individual choice instead of at the alliance level, especially if you have different areas of the titan to select from that are different levels. If at the alliance level, how would it be decided which area the alliance hits? Hopefully not by the alliance leader 
At the player level, the player could decided what level best fits for their titan attack team. Since alliances typically have a range of players, this would allow each player to play according to their team instead of the attack strength of their alliance.
Of course, this is only relevant if the super titan has areas with different difficulties. If it’s just a single area with the same difficulty (As normal), then everyone just hits. But I really like the different areas/levels as this would make it different enough from a regular titan to gain interest within the player community.
I think the logic currently used for titans could be used. The lower the *, the less chance of good ascensions mats, etc. BUT, I think this would be a great opportunity for SG to tweak the %'s up for getting ascension mats. It would be designed to be a difficult event, so should be treated as such.
If areas/levels were implemented, there would also need to be some additional code that handles the thought of an 8* titan on Very Easy level.
Scenario 1: A set amount of flags that each individual can use on any area/level. PRO: If one area is killed then the player can continue to hit the titan in a different area and use their flags. CON: Would the player receive more than 1 titan chest if playing in 1+ area? We currently have the ability to play on different levels in some events and we get a reward for that, but this sounds like a slightly different scenario.
Scenario 2: A set amount of flags that can be used in only 1 area. PRO: This solves the question about getting multiple titan chests. CON: Flags are wasted if the area is killed before the flags are used.
Scenario 3: Flags are regenerated over time as they are with the current version of titans. Depending on how often a super-titan would spawn, this would only work if super-titans were spawning at about the same rate as a regular titan.
Thoughts:
- Players would get credit for killing a super-titan in their titan chest.
- Did I mention I love this idea?
bring the vote, bring the hype!