There is definitely a lot that is unexplained about the death of John Paul I ... it certainly seems highly suspicious. But I am among those who strongly doubts that if he was murdered, he was not murdered because he was some sort of traditionalist who was going to turn back Paul VI's reforms. On the contrary, the acts he did during his very short time as pope suggest he was going to accelerate things even more. For example:
He was the first of the Vatican II papal claimants to use a "papal inauguration" ceremony instead of the tradtional coronation. He was the first to completely refuse the tiara (Paul VI was crowned, although I don't think he wore the tiara again afterwards).
In his Angelus address of 10 September 1978 he said that God "is our Father; even more He is our Mother" which is at least a novel way to speak about the First Person of the Trinity.
He expressed a commitment to "renewing the Church" by implementing the Vatican II reforms.
Also, some of his actions before being "elected" "pope" would suggest he was liberal, such as:
In 1968, when he was bishop of Vittorio Veneto, he submitted a report to the Patriarch of Venice that argued that birth control pills should be permitted.
I'm sure there's more, but that's about the extent of my knowledge of JPI aside from the general reputation/impression I've heard from people who were around at the time of his election who were strongly of the view that he was very liberal and they were happy that he'd been elected because they thought he would allow things like aforementioned use of birth control. I don't know whether they were right, but it all paints a picture of someone who was unlikely to have been αssαssιnαtҽd for being an arch-conservative. I have heard that it was more about the Vatican Bank.