There is no clarity or statutory guidelines about how Governor or President is to exercise such powers. Therefore there are dangers of arbitrary exercise of such powers.
There are judgements, that if such pardon is granted or refused to any convict no appeal to courts can be filed because Courts are not given such powers.
But at them same time, there are judgements that if the decisions to pardon are not based all relevant material or are based on extraneous considerations, the High Court and Supreme Court can judicially review such orders can set aside them.
The President and the Governors do not have arbitrary powers to grant pardons or remissions.