I see what you're saying. But, he did include JFK's assassination and the Vietnam War. And the old show threw in plenty of other peripheral events which were adjacent to big social events, such as racial equality, gender equality etc.
Showing a Muslim-American dealing with the post 9/11 bigotry is a good shout. No reason they couldn't do both, either. And I'm not too sure how involved or how much say Bellisario will have.
Sadly, it's not as if there aren't countless examples of other (famous) atrocities or trends they could explore. For example, the rise in mass/school shootings. online/social media bullying, bombings, bigotry, sexism, etc. In fact, the majority (if not all) of themes which were applicable during the original run are still as relevant now and in the intervening 30 years as they were between the 50s to 90s. With a smattering of new ones, or a modern spin due to tech developments etc.
I wonder too, will the new show carry on the trend of 'before they were famous' cameos such as Buddy Holly, teaching Michael Jackson to Moonwalk, Elvis, Chubby Checker, Stephen King etc and, if so, which they'll have.