I like the idea - moving more efficiently as a group while requiring more careful positioning and risking different AROs. I think that the real problem is the way fireteams buff their members in a way that strongly incentives the whole "4 cheap cheerleaders and 1 shooter". I only started using them when OSS came out, and I find that while incredibly effective when used correctly they also made even more games come down to whether or not my opponent can disable my fireteam on the first turn before I get theirs. Perhaps making it so the advantages sectorials have trend more towards providing new and unique loadouts and unit availability than numerical bonuses to shoot things would be interesting.