Not to be a Debbie downer, but I honestly hope not. We can't watch the games at a reasonable hour in North America, the travel and time zone changes are excruciating for a baseball team and could have collateral affects on their performance.
The play football once a week, so easier to integrate into a schedule. However, where are you going go get a week gap for baseball. Anything less is putting the teams playing in the UK at a disadvantage when they return.
Also, it seems like just a gimmick. Many other markets which are more lucrative for MLB to expand to then the UK, so apart from a gimmick, why....?