I'm not too concerned with transitions from solid to infill - as you say, it can be better in some circumstances for them to run the same way - I can imagine that may be the case. BUT you cannot choose the directions of the solid layers - and there is no information on the orientation that S3D chooses for a particular solid layer (apart from it being alternated from an immediately preceding solid layer).
Yes, I see that you can choose the directions of the infill layers. You can choose whatever works best for your particular print. On some of my prints with different patterns, the prints frequently work better if the first infill layer is in the SAME direction as the last solid layer, so I'm glad they made it an option. If you want it the other way, swap them to +45 and -45 (do the positive angle first). So if you want the first layer to print at -45 degrees, then you can enter infill angles of -45 and +45.
They let you choose the directions of the infill layers.
Maddavo wrote:I believe that S3D has a bug here and that the first solid layer above an infill should change orientation with respect to the previous infill layer.