So? It was to show that Stark was so far gone that he'd be intoxicated while wearing his Iron Man suit, and endangering those who attended the party.
But since he didn't injure anyone the whole scene came off as goofy.
Of course it didn't. Do you want Stark to actually hurting people? Why would audience cheer for a superhero who'd cause physical harms to innocent bystanders? This is still a superhero movie, not a character study on the consequences of an addict.
I'm not asking him to slap Pepper during his little dancefest. Honestly, I just want a better reason for Stark to decide to get his life together other than Fury giving him his dad's unfinished crap.
Avengers actually didn't occupy that much screentime in IM2, and both BW and Fury (and Agent Coulson) all moved Stark's plots along. IM2 has its flaws, but The Avengers tie-in isn't the reason. If they had beef up Whiplash's scenes and gave Varko more depth, eliminate or actually made Justin Hammer a legitimate threat, improved the slow middle part, and made the final battle vs Whiplash a real climatic finish, IM2 would've been a much better movie.