This is not an April Fools question. I believe Cust and Ichiro are extremely similar albeit under a very limiting set of conditions: offensive contribution per-plate appearance for the duration of their careers.

My evidence is novel. A friend and I have built a rating system whose metric finds Cust and Ichiro similar. The system is a generalized Elo-type model allowing comparisons between any pair of players.  Cust and Ichiro are similar because they exceed the Major League average hitter rating by like amounts for the duration of their careers.

My goal here is to introduce people to the rating system and to share some Mariner content. The similarity of Cust and Ichiro is just one tidbit from a near-comprehensive collection of player and team ratings dating back to 1950.

Here are a few links to spots on our website with content that is Mariner-specific.

Ichiro page

Mariners' team page

Mariners' team ratings graphed

I hope this is of interest. Comments, suggestions, and questions from an informed audience are extremely helpful.  Our work is still in a formative stage, making feedback all the more important. 

We call the rating system Southpaw because we are left handed.

Thanks,

Charles