Good post mate.
There's definitely an investment case for a new stadium and also one for a redeveloped Goodison, particularly when there are significant capacity and revenue constraints on the existing asset. Admittedly the initial return on capital is fairly low, but as you yourself point out it can significantly increase the asset value of the club.
Previously I have shown that a stadium with capacity of 50,000 including around 4000 executive seats could at capacity increase existing revenues from less than £20 million to £35/38 million without eye watering increases in ordinary or concession seating. If you add in the reduced running costs of a new stadium then you begin to see an acceptable return on say investment of upto £250 million.