We clearly have slightly different perspectives on this. The media gave him a rough time, perhaps unfairly and certainly not in a very enlightened way, but I saw the interviews and thought he was obviously very uncomfortable and came across as disingenuous - he didn't, as far as I can remember, say he thought gay sex was a sin, but what others do is their business. He said 'we are all sinners' but claimed his personal faith was separate from his political beliefs, which was clearly untrue as he has now admitted. Anyway, as you say, he was a weak leader. I do think the beliefs of our representatives are relevant to voters, because if the beliefs are sincere and deeply held they really should dictate their approach to policy. Obviously most people, including politicians, who say they are Christians are so in an almost entirely nominal sense, it's not a daily element of their lives.There were plenty of instances where Farron addressed the conflict between his views and his leaders role in just the way you suggested. The media found it productive for propagating their preferences to comment snidely and paraphrase in their headlines and top paragraphs before sometimes deigning to actually quote him somewhere near the bottom. As I'm fond of saying, most people don't get past the headlines before they form (or more often, reinforce) their opinion. Many then focused on his appearance as if that were a valid critique of what he said.
I think the Lib Dems will be better off with a more secular leader and Farron will be personally happier. He wasn't good at it and the Lib Dems made a mistake focusing on Remaining as their main policy. Compared to austerity and social inequality, it has no traction and they couldn't convince voters to agree that it was the most important issue and therefore vote for it. I didn't, and I'm a natural Liberal voter.