Marius, I've got the 1.7-10 x42 z6i on my 30-06. It is without a question the finest scope I have ever seen. The illuminated reticle makes a huge difference on a dark animal at low light. I don't know if that matters to someone in the trade who has plenty of opportunities to wait for a shot in good light, but then again, in good light, the need for a optically great scope is not much. If you actually need the excellent optics of the Swarovski, it means you are shooting in low light, in which case the illuminated reticle does make a big difference. Last year in Namibia, I was able to make a clean shot on a waterbuck at last light. I could see it easily due to the excellent optics of my scope, but could not have placed the shot well without the illuminated reticle. The day/night settings for the illumination plus regular cross hairs that work without batteries give you a lot of options but no complexity. I am no fan of complexity in my tools.
As far as the original question, I personally wouldn't go with the 2-12 on a 375 for mixed PG/DG use. I'd rather have the 1-6 for DG, and 6x is enough for me under most circumstances on plains game. I don't think I've shot any animal with my scope on even 6x. I keep it on the lowest setting and turn it up if I need to. That said, I do have a general preference for less magnification that a lot of people seem to have on plains game. If you are going to use one scope for both, I think the dangerous game side of the equation is more critical than the plains game side, even though it will almost assuredly be used more on plains game. The dangerous game is, after all, dangerous, so if a compromise is to be made, I think it should be made on the plains game side of the equation.
A ballistic reticle is interesting, but I would find it a distraction for DG and don't see need for it on plains game. If the animal is far enough away that I need drop compensation beyond holding for the top of his back, then I'd rather stalk closer.