Finding new and more efficient ways of doing raid mobs is part of the fun. I don't believe any of the current ways guilds do raid mobs would get them banned or in trouble.
Of course, people in classic wouldn't know as much as people do now, thus why there are new strats so bringing up how things were done in the "OG" days is kind of irrelevant other than for bringing up old memories. It's like the "back in my day" type people.
That being said, special strats for raid mobs especially classic through velious is also pretty irrelevant with the current knowledge of players, which has even increased significantly in just the last few years.
For example, even back on Phinny and recent prior TLP's, there was a very very small % of players who went just straight resist gear to nullify all the AE's.
In TEB we pushed very hard for everyone to just go straight resist gear, and in Kunark did not exploit any AE's on Trak or VP dragons to make anyone who couldn't resist the AE's have to dodge. In velious we never did anything special with raid mobs either, never summon kited AoW and the tov dragons are rooted anyway so not like you can re position them. Luclin we have done nothing special or any exploits with raid mobs to my knowledge either.
End of the day, let people do what they want to do in DZ's in my opinion. If they can figure out clever ways to kill raid mobs with fewer numbers, dunno why anyone should care. In the classic-velious expansions just go straight resist gear and not care about your stats and you won't have any trouble with any dragon no matter where you choose to do it. Resists = more dmg than maxing your stats.