@willowisppsi On the contrary, from what I've seen, aeon are the BEST at stopping this, since their TMD is quite effective against a billy!
4 aeon TMD, spread around the game-ender, seem completely reliable in stopping billy missiles without them even exploding!
Other faction's TMD, OTOH, have a billy explode into shields before 4 surrounding TMD can take them both out, requiring a bunch of shields to stop the billy from doing damage!
[edit - I did a bit more testing against double-billy launches for this
- UEF and seraphim require 4-8 TMD to be positioned between the ACUs and their billy targets - spreading 4-8 around the target is ineffective.
- Cybran sometimes just about get by with 4-8 TMD spread around the target - but I'd get extra just to be safe!
- Aeon are by far the best (Aeon TMD OP since forever! :D) - Aeon TMD can reliably defend against double-billy nukes even if they are spread around the game ender being defended. In fact, only 1 aeon TMD is needed for reliable defense against double-billy (2 if you want protection from every angle)!
'4-8', means 4 if the firing ACUs are 30 range units away, and 8 if the ACUs are 256 away.
Overall, the best defense against double-billy is probably a combination of shields and TMD. Enough TMD to shoot down a single missile (~6 in a circle around the game-ender, unless you're aeon, in which case just 2 on opposite sides seems fine). and enough shield to tank the rest!
I'm sure it's possible to co-ordinate a double-billy between shots of aeon TMD, but have you ever tried that even when you're NOT co-ordinating your timing with another player? The 'downtime' on aeon TMD is REALLY small, and the 'uptime' gives basically missile-invulnerability!]
Perhaps most crucially regarding what you were saying - all factions can defend against double-billy with sufficient TMDs - or even IN-sufficient TMD and a shield or two!
(I only tested about 60 nukes - there might be positions where this changes, but I did try to get close to the target as suggested. figures generally depend on range - the further away the billy is launched, the more TMD are needed to stop it before it hits a shield and blows)