Related to the intended use question is how does what you have now NOT do what you intend? The .30-06 can be loaded nicely hot with modern bullets and powders to do a lot of what the Win Mag does. The decision should be made based on problems or limitations actually encountered.
I didn't see the 30-06, a round my brother in law tells me is altogether diff than the Winchester 30 I have...... At 70, there are too many things I don't see. But I keeps on trying.