Full control over projects and enterprises is always nice, particularly creative projects. Or at least, it always feels nice. A nice thing about Zazzle then (and presumably other print-on-demand companies), is that Designers have full creative control over their work. Sure, Zazzle does have a few restrictions for art and photos (for instance, nothing that can reasonably viewed as discriminatory, nor anything that encourages drug abuse, is excessively violent, nor obscene or pornographic in a non-artistic way), but in all reasonable and understandable ways, Designers are free to create whatever they want. Of course, this extends to whichever products to post as well, plus, how to organize and present them.
Yet one is always well-advised to re-evaluate their work and practices at times, and as with being part of any community undertaking, overseen and managed by a third party, sometimes, Zazzle makes changes that encourage, or even force, Designers to react. Zazzle does these things, of course, not only in their own best interests, but those also, ultimately, of their Makers and Designers. And while such changes can understandably be frustrating at times (and granted, not all changes will directly benefit all Designers), taking time to adjust to and occasionally limiting what one can choose to do, if nothing else, they are, again, simply a part of creating and selling in conjunction with a company.