I think fireteams should not be limited to three, especially when a raid and crucible are the only activities that can have more than that. The first thing that comes to mind is Patrol. Why can't a bunch of friends screw around together in the oh-so-open world we have? I can't think of one reason why four or more is way too many for this activity. A strike doesn't have to be just three either. While I do see some sense in limiting a strike to three, I don't think it should stop there. There are many ways to design a strike to accommodate a group of guardians. Your thoughts are most welcome.