What should I look for in a cream for crow's feet?

See your MD. Your qualified facial plastic surgeon will be able to recommend appropriate treatment based on your specific needs. Topical treatments (retinoids, skin medica, obagi, etc) can be helpful, but of limited effect. If you have more significant wrinkling you may benefit from additional therapy like botox, peels, lasers, or blepharoplasty.
Elastiderm. Obagi elastiderm is clinically proven to increase eyelid skin elastin. However: I recommend a combination of botox, laser resurfacing or chemical peel, and possibly blepharoplasty (eyelid lift) in addition to at home skin care. Retin-a should be used sparingly on the thin skin of the eyelid area. Hope this helps!
Peeling effect. The cream should have chemical in inducing exfoliation/peeling effect. One of the standard is tretinoin/retinol.
Crow's feet cream. My preference is skinmedica's tns eye repair, which consistently hydrates, brightens the eye area. It contains tns, peptides, vitamins a, c, e and chrysin, boron nitride among others, to improve fine lines, wrinkle and dark circles. It is physician dispensed. For long term improvement, combination therapy is best. Agree that fractional resurfacing + botox/dysport +/- bleph will give best results.
Collagen building. There are no perfect creams out there and alot of selling. Creams that have shown to be effective are low dose retrinols that help build collagen and elastin. Neocutis has a great eye cream with growth factors that seems to work well in clinical studies and real life. Use sunblock regularly and stay out of the sun. Also wear sun glasses.
Specific for eyelid. Eyelid skin is much more sensitive than the rest of your face. There are specific eyelid creams with milder chemical activity that hopefully do not create inflamation of the eyelid (I have seen many such inflamations with the wrong the cream). Botox is the most effective for crows feet.