It is not as bad as we perceive it. There is a difference between arrested and convicted. Were it not for this bill, i (instigated by another politician) can file some random case against a politician in my neighborhood during election time and prevent him from contesting. Here the policeman has the arbitrary power to decide who will contest and who will not.
People participating in every movement would have cases slapped against them. For example almost all farmer leaders in Karnataka have had cases slapped against them (cases like unlawful assembly and such). So in theory those with money and muscle power can prevent these guys from contesting just by getting the police to revisit the case and arrest the person. Just an example.
It is true that this can result in some misuse but it is in the right direction IMHO. But those convicted of serious offences (supreme court has said 2 yrs and above jail term) should not be allowed to contest - that is for sure and nobody should have any difference of opinion here.