Both pro- and con- positions have merit, but I’d like to see it done, if only to increase our understanding of the process and biology. The Thylacine seems as good a choice as any… A large, easily studied animal, but one that stands little chance of restablishing itself in the wild without massive human intervention, and thus relatively proof against escapes or accidental reintroductin in an uncotrolled manner (as opposed to rats and rabbits, fer instance).
A large, modern, well-designed museum-preserve doesn’t seem too cruel a fate for a ressurectred species to me…
IIRC, the Japanese efforts to clone a wolly mamoth have at least temporarilly foundered on the issue of obtaining viable DNA.