Exactly! Vito had all these grand plans seemingly “pretty straightforward” “but not quite workable” indeed

Sure thing Senator or Governor Corleone and Corleones' illegal side of the business, just cannot coexist!

Besides, in conjunction with
What did Michael want for Anthony?
Originally Posted by Turnbull
Extract: That would have made Sonny the head of an ever-diminishing criminal side of the Corleone family, and made him, in effect, Michael's strong-arm protector. It would have set up powerful resentment by Sonny, possibly leading to deadly violence--and an interesting additional GF movie

Again, Vito had all these grand plans but no forward-thinking / planning including the family turmoil, it would cause