Well then, i don't think you needed a MacBook in the first place.
Here's how I see it:
iMac, iPad, iPhone. To be ideally fine.
MacBook Pro, iPhone. To be fine.
MacBook Pro, iPad, iPhone. To be useless.
iMac, MacBook Pro, iPhone. To be fine.
iMac, MacBook(Pro), iPad, iPhone. Is an overkill, and useless.
If the iPad replaced your MacBook, then congrats!
Very good way to look at it. I had a similar revelation when I first bought the iPad. I have iteration #3 on this list and realized I really should be at iteration 1.
I think you could maybe add macbook air where ipad is represented if a lightweight device with a keyboard is essential