What if any ship could have multiple cores but the number of cores allowed would be determined by cost or mass? Or perhaps an additional core is required at certain cost/mass thresholds? My reasoning is that because every ship has one core and the only way to destroy a ship is to destroy the core, the most effective ships have large amounts of concentrated fire. This means that a large number of small ships is far less effective than one large ship as they do not concentrate fire on one point, leading to small ships being no more than stepping stones. If larger ships had multiple cores then the dispersed damage of smaller ships would become much more useful, though still less effective than concentrated fire. Additionally, larger ships would feel more like capital ships and less like death stars.