Thats systemic to the chapter right now AnotherDilbert - I wish it was just Meson bays.
Keep in mind that section is a bit of shambles right now (nothing against Matt of course, we gotta prioritise after all) - for example, Particle Turrets and Plasma guns are better than their barbette equivalents (due to triple turrets.. 3D+6 vs 4D, for less cost, less weight haha). Fusion guns are monstrous when in triple turrets at 4D+8.. etc
Matt wasn't concerned because perhaps, in the High-Tech universe, barbettes just dont exist because more efficient, more powerful version exists until you get to the bays... so it would be the same with Meson bays. In that world, you dont have Meson Spinals because Meson bays are way more efficient!
I think we should take a look at it regardless in the end...