This is why creeds exist - so that people can tell others what part of Scripture is truly "vital"... and that which is not. The problem with that process is that fallible men are the ones claiming such principles. Also, you never find Jesus saying "now THIS is important, but not my other teachings". However, He DID say that whoever abides in His teachings would make one a true disciple - implication being ALL His commandments (John 8:31-32). The "hot discussion topics" as you call them are part of God's revealed will... and DO have a bearing on one's salvation. If not, God went to a whole lot of trouble to reveal His will just so we can say "this is important and this is not."

As far as love goes, I agree that it is foundational to our faith. However, one must define love from the way it is defined in Scripture - not the way man wants to define it.