A cerec crown would not result in overlaping margins (decay prone), in most cases? can you guess that i'll be switching my dentist?

Maybe: Why don't you tell the guy he may have screwed up. If it is true, and we all make mistakes, he'll probably be glad to redo the thing.

Quality?: Crowns of any type should not have bulky or overhanging margins. There are degrees or variations from ideal or the norm. If you are not happy with your dentist, then the dentist should be made aware of it, informed why, given the opportunity to make amends in a manner mutually satisfactory to both. If the quality is not there, you are totally justified in switching.

Consult doctor: You may benefit by telling the original doctor of your issues as they may not know and would want to know and also fix if need be. Many times doctors do not always know if something is wrong and if you do not alert them, then they do not have a chance to address the situation. Most doctors want to fix and satisfy you. Open the lines of communication.