Was waiting to hear from the board before I chime in.
My opinion is that he should be, but likely won't be. Mariano was a blip. A freak. It may never happen again.
The reason, I believe, is that there aren't machines that are making induction decisions... machine that use batting averages or WARs or gold gloves to empirically calculate their votes. If there were, lots of candidates - like Beltre - would be unanimous. Pujols should be unanimous. Trout should be unanimous. Ohtani should be unanimous. They easily meet the criteria for HOF induction based solely on their numbers, so a bunch of AI decision makers would unanimously induct them.
The fact is, it's a bunch of folks from the BBWAA who decide. They're human. They cast ballots based on more than just numbers. Maybe they don't cast one for Ichiro on his first year because someone else they feel is deserving is on their last year of eligibility. Maybe they are purists ("I won't vote for Bonds because anyone tainted with PEDs never gets inducted"). Or traditionalists ("I don't think we should count 1,300 of Ichiro's hits from his career in Japan"). Maybe they think no one should not be elected in their first year. Who knows. It's an intrinsically human endeavor, and as such it is as unpredictable as any election ever is. So unless he is the only name on the ballot, he won't be unanimously inducted.
D-Train - we have respectfully disagreed in the past, and I think this is another one of those cases. I don't think a side by side comparison of Beltre and Ichiro is fair. Yeah - Beltre hit for more power and put up more WAR. But of course Ichiro started his career in the majors at a time when most players were peaking (and had accumulated stats and WAR for several years). 1,600 of his hits came when he played in Japan - yeah, the competition is less than MLB, but they also play 30 games less per season. Ichiro's style of play was different - he never wanted to hit homers, even though he easily could. He was the best leadoff hitter of his generation, and he was a a defensive wizard. They're just different players.
You can line up the trophy cases, and Ichiro is just as impressive as Beltre. But here are 2 other factors that I think are relevant: first, Ichiro is the greatest player to come out of Japan not named Ohtani. Second, he paved the way for Ohtani. He did for baseball what Wayne Gretzky did for hockey - he normalized it. He brought fans and players from Japan to the US. He expanded the sport. And his career was never tainted by controversy, and he did it all without PEDs.
So yeah. I'm babbling. But I contend that Ichiro should be a unanimous, first ballot inductee. There shouldn't even be a question about it. But I doubt it will happen. Sadly. For me, at least.