Do my Zirconium crowns need to be replaced? (photos)

i feel you are not happy with your crowns. issue is with aesthetic. but for that you have to visit cosmetic dentist. all dentists are not cosmetic dentists. basic issues are aesthetic, torque, spacing distal to canine,  gum line cant. 

They don't "need" to be replaced. But for better esthetics and a more natural color, they would need to be replaced. First, I would address other issues such as the uneven gum height and straightening the teeth. Once the teeth are in the proper position and the gums are even on both sides, it will be much easier to obtain a more esthetic result.

If you are just interested in fixing just the one issue of the unnatural shape and color- then yes, replacing the crowns is possible and they should be able to give you a better shape/color- although the orientation of the new crowns is limited by the crowding on the bottom- which means a comprimised result.
The good news is that yes this is absolutely fixable, the bad news is that if you want it truly fixed it requires trouble-shooting other areas. Part of the problem here is the lack of symmetry on your gums and the crowding/spacing of your teeth. It looks like the height of your gumline around the new crowns is significantly different than the other side, and also the unnatural shape and orientation of the crowns has left you with a large open space and proclined teeth. 
Creating a truly esthetic result would involve a simple gum contouring procedure (gum lift) on the left side to create symmetry, properly aligning your teeth, and replacing your existing crowns with more natural looking ones. Some of the challenges would include getting an exact color and shape match, and also dealing with the interferences caused by the crowding on your lower arch. If you really truly would like to improve it, it is a good idea to consult with an orthodontist first about solving the crowding so the new crowns can be lined up correctly, then visiting a cosmetic dentist to place new crowns and possibly add veneers on the other side to create symmetry. It is extremely important with cases like yours to choose a well-qualified doctor and lab- and you absolutely should be advised to get a "shade match" with the lab. This is standard practice for cases that involve matching other natural teeth in the smile zone.
 I am more than happy to answer any more questions or help you a good Dr in your area if you'd like to message me privately. There is one particular amazing cosmetic dentist in Indianapolis that would be great help for you. Best of luck!