You forgot the part where a bunch of the boss fights were completely broken to the point of guilds having to cheese them, and Blizzard didn't bother to do anything about it because they had no plans to ever fix those bosses. Spoiler alert, they never did. They also hyped up the 10 man raid size as a viable raiding alternative to 25, and then never even bothered to balance raid encounters for 10 mans. They just adjusted the bosses and adds' health, and even then, on some fights they didn't. We've seen exactly how much effort they put into classic, you're incredibly naïve if you think they'll work on those now when they couldn't be bothered to when it was the only expansion.