One important point to be considered is if  root canal of the said tooth/teeth done? We can take the teeth inside of the root canal is done. Colour matching can be done with the new crowns.

Hello,Apart from color shading there should be proper proportions then only it’s looks better but keep in mind proclamation can be correct with more tooth preparation ( cutting ) but it’s also very important parameter that u gone through root canal or not because more preparation possible only after rct so please more careful about your healthy of your tooth

Hello Please replace or heck with your old dentist

Yes definitely its true Better  replace it with zirconia

Shade matching is an important component of crown fabrication process, and sometimes we even take the patient's opinion (as an optional procedure and not as a rule). And the Crown preparation is definitely done in a way that the final width of the crown is also taken into consideration, so we can say that it is not protruded because it is a Crown but because it was not fabricated properly. But this is a tentative suggestion without a look at the clinical condition of the affected teeth. You can post a clinical picture for a better opinion from our side. Regards.