The default sensors.conf file is very large now (2450 lines, 70 kB). This has a bad impact on performance. Compared to a custom configuration file for a specific motherboard, libsensors initialization is more than 5 times slower.
On top of that, many statements in the default configuration file are specific to a few motherboard models, or correspond to recommendations which motherboard manufacturers may or may not follow. This can be confusing for new users, which expects displayed labels to be correct.
I suggest that we strip down sensors.conf.eg to only include labels which we know are always correct (e.g. internal voltage labels.) There aren't that many so this should lead to a reasonably-sized default configuration file. Recommended wirings and scaling factors should be documented in a different place (kernel tree? wiki? man page?)