A former Arrowhead Studios team member recently discussed the design process behind Helldivers 2, specifically regarding squads, explaining that prior to launch the studio had experimented with larger team sizes. This simply didn't work the way developers wanted, with the four-person limit in Helldivers 2 now being one of the game's defining features. This, of course, hasn't stopped players from wishing for expanded squad sizes, but considering what Arrowhead had to say on the matter, four players is likely the sweet spot.