Why keep the multiple-launcher entry?

Clockwork Goblin just brought over the T34 Calliope from Bolt Action into the new Defiance book and like allot of other entries the transition was another cut-and-paste job. The Bruin and now the Heuschreck reformulated the concept of rockets as direct fire only howitzers and from what I understand that this is a trend that will continue in additional books. So why not retro actively fix the nebelwerfer/howling cow (hell the Heuschreck has one on top of its head), Calliope, Katyusha and Panzerwerfer/Stuka-zu-fuz. If they want to maintain the spread effect just make it an additional attribute for unlike bolt action this is a game that will need and require more and more attributes.