I hear you on this bro. I've completed normal mode many times and hard mode once, legitimately. It was a great time. Me and a group of friends were lvl 27's doing the vault for the first time and took us about an hour to do the opening stage to get into the vault haha. We didn't look up how to do it or anything, we wanted to figure it all out on our own. Same went for the templar, gate keeper and atheon. It took us a good while lol. Now that I've done it many times, me and my group will occasionally agree to just cheese the templar and move on quickly seeing as we have tight schedules. But remember, it's not glitching persay. Yes, bungie had a certain mechanical way to beat each boss, but what they didn't figure is people are smart and will figure out different/easier ways to beat the bosses and it just so happens that pushing him off the ledge was one of those "easy" ways lol, or killing him from a sniper platform. They are all strategies people came up with.