This is more of a philosophical question than a scientific one. I cannot think of any ethical considerations of cloning dinosaurs that wouldn't also apply to cloning any other animal.

Like other vertebrates, dinosaurs' DNA has extra buffer strands ('telomeres') at the end of each chromosome, and which are eroded when the cell divides. Only the germ-line cells (sperm, eggs) don't erode these telomeres. This is an important factor in causing aging. For this reason, you wouldn't want to clone an animal from a body cell unless you had some way of regenerating its telomeres. This would apply to humans, dinosaurs, and most other animals (it doesn't apply to plants, though).

Also, large-scale cloning will have impacts on the gene pool of a species that might be undesirable. Depending on the species of dinosaur you are trying to clone, this may or may not be an ethical issue. For example, if you're cloning a species of bird, especially an endangered bird, then flooding the gene pool with genetically identical clones would reduce the genetic diversity of the species, and possibly make it even more at risk of extinction due to this low genetic diversity. If the dinosaur species you are cloning is already extinct and you are cloning it to restore it to life (say, a passenger pigeon), then you're already helping it.