Did they say why Infinity Slayer is 4 v. 4...

Games Other Halo
1

…instead of 6 v. 6?

2

Because some playlists should remain 4 v 4, most likely.

3

Slayer has always been 4v4, except for Social Slayer which was 5v5…

4

Team Slayer is usually 4v4.