Do you think humans should be engineering human dna?

no. there are several reasons

1. there is natural process of human make up,which if disrupts causes many disabilities. like mutation, as science has achieve many but can not engineer a perfect solution.

2. DNA have a certain pattern which if changed could made a human a liability. like getting genes from a sheep and engineered it in a lion which posses other traits. such causes an imbalance in the ecosystem and disrupting the biome. Loin behaving like sheep and sheep behaving like loin.