I am working up some new loads for my T/C Contender 204 Ruger rifle and found the first bunch of fired brass exhibited flattend/dimples primers. These ware no hot loads. For a representative example one load was 28 gr Varget, CCI 400 primers, Hornady V-Max 32 gr bullets and used both Winchester and Hornady brass.
I haven't seen a factory rifle that doesn't. It's kinda scary at first but, a bushing is the only way to fix it. I haven't had a bushing installed on my XR-100 and haven't had any problems. The primers still crater just like yours but I've never had any pierce.
I have never heard of increased nor reduced accuracy associated with firing pin bushings. The smaller high pressure cases like the 204 Ruger will induce primer flow if the firing pin hole is too big. A firing pin bushing will improve ignition consistency though.
If I was planning on hot rodding my 204, I would consider a firing pin bushing. I would also invest in a GOOD scale. (Denver Instruments MMX-123) The case is so small and builds pressure so quickly that an error in charge weight near max could be very dangerous.