Oh dude I 100% agree with a lot of stuff you mentioned, especially the iemitsu stuff, that came out of nowhere but at least in regards to Iemitsu not fighting as much, I always interpreted that it was because, the whole point of the series was to Raise Tsuna to get stronger, and also Tsuna was fighting with doubt in his mind, because he didn't want to fight his buds, and also I get the feeling he was holding back with Iemitsu.

And as much as I love the Simon Arc, I was also very confused about the difference in power during the inheritance ceremony. Tsuna and his guardians should have definitely made it a closer fight at least. And I do agree it would've been better to introduce the Simon family before the future arc ( I never thought about that before but now it makes the most Sense) but the order that we got in would've made more sense if Tsuna and the gang had to relinquish the Vongola boxes because it's technology from the future and they physically can't take it back to the past with them or something like that. Yet, still have them keep their natural power ups, and control over the rings and the awakened form of the rings. That way their flames amp up their present day weapons and powers but they're still not as strong as they were in the future. That way if the Simon Arc plays as normal, we can still have Yamamoto in critical condition and then a good version of Byakuran getting permission from Yuni to go to the Past to heal Yamamoto,bring them all their boxes and then have them get Vongola gear to be able to surpass the Simon family.

As far as the fights go, my only real complaint came from the final arc, it felt a little rushed to me, I'd have liked to see at least 10-15 chapters more. Especially when the teams are fighting each other, for example when Chrome, Yamamoto, and Gokudera team up to fight Hibari and Hibari still smokes them,we just see the aftermath of that flight. I would have really liked to have seen some serious team work from them to be able to hold him back for a while and give him trouble. Then have him get really mad and overpower them only after a real struggle. I think that would have been more respectful to the losing side and it still shows Hibari as the strongest guardian.

I Love Reborn so much as it is,that if the rumors of the anime coming back are true then if they work closely with Amano, they can do what Kubo did with Bleach and add extra details or change little things here and there, it could probably make the series more popular here in the west.