I agree to this, Wedding photography is not only hard, but it can ruin a person if they don't know what they are doing. People get sued left and right for not meeting to the client's standard. Best way to get training is to be under another wedding photographer and go from there.
the key to weddings is to remember its a marathon not a sprint. anyone can get a couple of great shots but its getting good shots for 8hrs in all lighting cond. thats the key.
also having business insurance is important. photographers can be liable for flying people back out to get family pics they screwed up. if you dont think that really happens... your wrong.
also about shooting conditions in a dark church. i know many disagree but i always use flash unless someone tells me i cant. the client (the bride and groom) are almost always interested in capturing the best pics then preserving the sanctity of the ceremony. again if you dont believe me ask your client.

