In Maha-parinibbana Sutta, Buddha said "if Sanga want, after I completed Parinibbana, you can remove small and/or light codes from Vinaya". Why Buddha said this approval to Sanga? Is it a kind of testing to future members of Sanga whether they can completely comply the Vinaya or not? This approval may lead to breakage of Sanga to Mahayana, Theravada, and more. This approval, is it being served as a reference to other parties of Sanga who cannot comply the vinaya completely not to be blamed by normal people? Or is it just a question to just Sanga at the time of been said and this was the way to be. Or any purpose of this approval? Or is it totally not approval, and just question?
If the Buddha had totally approved the removal of certain rules then the Buddha would have explicitly mentioned which ones.
In the 1st Council the monks could not decide what extent was minor rules, so ultimately decided to keep all the rules with the fault of not clarifying being with Ven. Ananda when the Buddha mentioned this.
The original sangha had no rules. The rules arose in response to specific situations. The number of such rules is given as 150 in the suttas, but there are 227 rules for male monastics in the Theravadin Vinaya. The Buddha was dissatisfied with the state of the sangha toward the end of his life. He refused to appoint a leader of the sangha after his death. He also stated that the lesser and minor rules could be abolished after his death.
Contrary to many modern monastics, who boast concerning the number of rules they follow, Mahakassapa said that the number of rules is inversely proportional to the state of spirituality in the sangha. If you analyze the pratimoksha, you will see that there are really only about ten fundamental rules (see my "Synopsis of Vinaya"). These are not that different from the precepts of the vow of the bodhisattva. Elsewhere the Buddha makes it clear that following rules is a relatively minor thing, contrary to the aforesaid monastics. This provides context for the Buddha's injunction, which was not honoured by his immediate successors. The rules of the Vinaya became a major point of controversy that led to the first schism.