Because adding turrets isn't as simple as deleting one.
Re-orientating the turret model can't be done in PCS2 if you say, duplicate a turret. Adding a turret requires exporting as a DAE, going into whatever modelling program, adding a turret, rexporting to DAE, and converting back to a POF if you don't have the source model (or if the source model is not in a format you can open with the modelling program you have).
If there is a demand for a model with extra turrets (or if the creator just wants to), it's less work for everyone just to have an extra turret there which will be deleted for the MVPs version.
Therefore, it is less work to delete a turret than to add one. So let's not go into debates about extra turrets. People should just shut up and stop complaining about them because THEY AREN'T A PROBLEM UNLESS YOU MAKE THEM ONE YOURSELF.
If the FSU people are really too busy to even do something like deleting turrets in PCS2, then I'll do it >.>
But right, back to the model. The girders are...iffy. Especially the ones on the bottom. Drop them and replace them with something closer to the texture on the original.