A one time use 58 boost will not kill low level leveling dude… Mage boosting already did that. Anybody who has a 60 already is going to be rushing through the dark portal and going to be ignoring azeroth for atleast a week until they hit cap or close to it.
The people who don’t immediately do that will be leveling draenei/blood elves and breathing life into azeroth.
The 58 boost is only going to benefit the people who want to try a new class they haven’t already leveled or people who quit early because azeroth was already dead due to mage boosting.
As far as the gold farming complaint goes, you’re complaining about a symptom and not the real issue… gold farmers are going to do their thing no matter what, I’ve grinded elemental earth alongside the same farmers since my first level 60 on classic… the real issue you should want addressed is blizzards lack of GMs/support teams to root out and ban RMT players.