After reading what was posted here a bit more, I think I’m getting the main problem with this change.
Apart from min-maxing considerations and races that end up with a real disadvantage, people feel that this change adversely affects the identity of Faerun’s races. And with that…..I actually agree. The races lose distinctiveness, which makes the choice of race less significant. In many contexts, I’d see this as a good thing, but as it seems to me, the (original) rules that apply to races are an expression of a distinctiveness that exists in the lore, and changing to the current system introduces more arbitrariness into the world and reduces diversity. Faerun’s races mostly maintain their distinctiveness, for whatever reason, and most players actually like that fact. Playing a dwarf should not feel like playing a human, otherwise why make the distinction in the first place? Attribute scores are only part of the race package, but even so an argument can be made that the rules should continue to reflect this distinctiveness.
So while the change may not affect most characters – after all you can just apply the new attribute adjustments in a way that reflects the old rules - it makes the world feel different. And that is significant. Some people do not like how it feels now, with more arbitrariness and less diversity. It is a minor thing to me, probably because I’m not so invested in Faerun’s lore in the first place, but I do, in fact, feel the same.
+1 This!. Well Put.
"They say he who smelt it dealt it." Sooo technically... this burnt corpse is your fault officer."