The humble Terminator squad.   One of the best looking infantry kits in the Astartes range. Chunky, classic, refined, simple... disappointing rules, underwhelming wargear.   It wouldn't take a lot to fix them as some perfectly viable versions exist with minor rules adjustments or additions, but are limited to the specific Chapters or Chaos Factions.   Starting with the Tactical variant:   -Allow squads of 5 to take both the Cyclone Missile Launcher AND the