Itinerary - should i do Hiroshima?

Im visiting Japan for the first time in late September/early october, my itinerary so far looks like this:

Im based in Tokyo for 6 full days (4 days ive got dedicated to the city and the other 2 im going to do a day trip to hakone and another day trip to mt fuji/lake kawaguchiko area)
Then ive got 2 full days in Kyoto and 2 full days in Osaka (not that much i know but im confident i can fit in pretty much everything i want to do here)

Ive still got 2 days spare to play with so my question is - should i go to Hiroshima?
People have told me its good for 1 night/2 days and i genuinely wouldn't mind going and seeing as many different places as possible but is it worth going down there for 2 days 2 nights at the most and then trekking back up to tokyo to fly home again?
Should i do Hiroshima?
Or
Do an extra night in both Kyoto and Osaka instead?
Or any other suggestions are welcome. Thanks

Hiroshima is only 1h30 away from Osaka (very easy to get to), so it all comes down to personal preferences. You don't need to go to Hiroshima even if it is famous (IMO there is really no such things as absolute "must see/unmissable" spots), if you have no special interest in it :)
Now if you are a war history buff, it might be an "unmissable" visit for you. But I suppose you would not be asking the question here if that was the case.

I preferred Nara to Hiroshima: beautiful and impressive temples/shrines, forest walks, cute cafés, smaller and older buildings. There's also Himeji (castle + garden), Kurashiki (pretty town), Hikone (castle + old town), and a lot more.

Add it all to Kyoto. 2 days ain't enough.

If you are already seeing Tokyo, you don't need much daytime in Osaka at all - evenings are when the city is at its best - go there after a day in Kyoto. I suggest you add a day to Kyoto, and add half to go see Nara Park. That still leaves you your time to go see Hiroshima & Miyajima.

Is there a reason why you are on the fence? Is it just the Shinkansen time from Hiroshima back to Tokyo?

If you are confident that your Kyoto days are enough to see what you want to see then why not go to Hiroshima? You say you are interested and you have 2 free days.

For a first trip I'd say the same as @H. Don't go to Hiroshima but add the days to Kyoto/Osaka. You can day trip to Nara, Koyasan, Kobe etc if you want.

I love Hiroshima but for a first trip I'd not try to cover too much ground.

I'd recommend Kanazawa. If you haven't booked accomodation yet you could rearrange your schedule to travel to Kyoto and Osaka via Kanazawa (part of it is covered by shinkansen).

It's much more interesting than Hiroshima.

I'd go for at least one night.

If by Hiroshima you mean Hiroshima City, it's a pleasant enough, modern Japanese city, with a nice downtown and some great food (Hiroshima-style okonomiyaki is my favorite Japanese food). That said, for the most part Hiroshima doesn't feel very different from a lot of other big Japanese cities, so if you're already spending time in Tokyo or Osaka, a lot of Hiroshima might not leave much of an impression. The exception to that, though, is Peace Park and the Peace Memorial Museum, though I understand that those aren't necessarily places that every traveler wants to put on their itinerary.

The one place I absolutely would recommend visiting in Hiroshima Prefecture, though, is Miyajima. Yes, Nara also has wild deer roaming through town, but Miyajima's mountainous terrain makes for, in my opinion, the more beautiful scenery, and the view from the top of the mountain is great, whether you get there by hiking or taking the ropeway/cable car. If you're visiting Miyajima, staying on the island is an option, but it's also easy to visit Miyajima and spend the night in Hroshima City, which has more restaurant/hotel options.

Another easy trip to make if you're spending the night in Hiroshima is visiting Iwakuni (which is in Yamaguchi Prefecture, but close enough to the prefectural border that it's only about an hour from Hiroshima City). Both the Kintai Bridge and Iwakuni Castle are nice.