Is 1.5 a good kill Death Ratio or is it bad?
K/D is not necessarily an accurate measure of performance. While it's a good and widely used quantitative indicator, you can't expect it to accurately capture the entire scope of a player's skill.
Trying to use K/D as the only marker of performance would be like if colleges only looked at high school GPA for admission. It does tell you something about a player, but in the same breath, it also doesn't say all that much.