Was lincoln's veto of wade-davis bill good or bad? and why?

This can be argued both ways.

Good: Lincoln's vetoing of the Wade Davis Bill ensured that the process of allowing the Confederate states to rejoin the Union would not be as difficult. The Wade Davis Bill called for a majority vote by Confederate citizens in order to rejoin the Union. At this time, a vote like this could have gone very wrong as numerous states would not have the votes necessary to rejoin the Union. Since Lincoln vetoed this bill, it never happened, probably saving the Union a significant amount of problems.

Bad: Radical Republicans probably saw this as bad, as they felt Lincoln's "Ten Percent Plan" let the Confederate states of too easy. The Radical Republicans wanted the Wade Davis Bill to ensure that the Confederate states would be loyal to the Union from now on. However, when Lincoln vetoed this bill, many Radical Republicans felt that the Confederates would allowed to join the Union again without much punishment.