i'm not going to insult you because i'd get an infraction, but it takes a whole, whole, whole lot of crazy wild logic to land at Cataclysm being the peak of WoW, initial curiosity doesn't equal a golden era, you need to remember cataclysm had a whole lot of hype generated by people like Totalbiscuit during the beta, instability shortly afterwards doesn't equal a golden era either. You need to remember the radiating effect of the expansion being bad had to multiply from friend circle to friend circle until everyone collectively left, upkeep of the initial idea that cataclysm sucked was delayed.
The game only grew from vanilla, AND BC AND TLK. All three were "golden eras" for WoW, TLK took what both Vanilla and BC laid down previously, it didn't utterly devastate massive foundations of the game like Cataclysm did. (see flying, leveling, raid finder)
The true sweet spot in my opinion is mid BC before BT. If I had my way I'd integrate that content and rebalance it for "vanilla".
I personally think Cataclsym was a great time period for fun balanced PVP, but not much else.