User blog comment:ShineKuzu/Mechanic Innovation: Same Batch/Set Bonus(!?)/@comment-24570336-20180601112312

Gonna give my own insight on this, since I recall Alim discussed about "Set Bonus" when BF2 was being developed.

The reason Set Bonus was only made possible in BF2 was because of the following:

1. BF2 is an entirely new game.

Alim could have designed the game to implement Set Bonus from the start. BF1 may suffer from certain Tech Limitation that made implementing the Set Bonus either impossible because of code limitation, or just difficult for a person to re-access every unit.

2. It's legally not possible in BF1.

Alim tried this before with the Meirith Batch (Quaid batch). They got in trouble that time because Claire and Colt had ES that required both of them together to work, and they are Rare Summon units, pulled from a random pool, which is forbidden by law in Japan. The issue was resolved by putting spheres in the Merit shop as an alternative to activate their ES. I doubt Gumi would even try this again, as they did with Ravenna batch.

So yeah, giving Set Bonus is not as simple as saying "Hey, completing a set looks like a fun way to play the game! Let's try this out!" without thinking about the pros and cons in-depth.