I would like to ask you something, how much experience do you have animating 3-d models with complex and constantly moving animations increasing and decreasing in size throughout play? How much experience do you have applying textures either static or moving to the fore-mentioned model? And how much experience do you have programming said model to do what you want it to when you tell it to?
If there answer to any of these is less than or equal to something to effect of (Little/very little/none), then you don't really have a right to tell them it's easy. Especially when riot has stated several times on the fact that (paraphrasing here) "Creating a new skin for Zac isn't as simple as changing the color, if we change what he's made out of, we have to change the way it would move too. Water doesn't move and fall off in the same way that goo does."
So to create a Tar skin for example, would probably have the tar constantly falling and running down his body even when idle. An energy zac would have constantly moving animated lightning. If Riot did a bubblegum skin, they would probably want to make pick up dirt or such over time (as that's what gum would do), and maybe have it fall off if he walks in the river. The reason Riot doesn't do pure color changes (Chromas) as skins for him is because they focus on quality over quantity when it comes to development of them.
Now if you do have the skills and experience to create skins for Zac, i would implore you to make them, submit them to Riot along with a resume, and work for them and get them all out there for Zac players to purchase. If not, don't claim that it's easy to do. They could make as many zac chromas as there are colors, but Riot isn't going to settle for that, if they're going do a Zac skin, it is going to be a skin, not a glorified overpriced recolor.
