Agree , I like the new layout and features.. I really don't think it detracts from simplicity.. realistically I think it makes it simpler so its a more integrated experience, and not taking users away from the site, and relying on 3rd parties like twitpic or twitvid. At the same time more proof to stay away from them as a platform. Can't blame them for what they did.

I'm pretty excited about this and hoping I get it enabled soon.

Centralising my experience inside just one page. No need to click on links to view, go back and reply.

It's adding just enough value to not drag it down in the complexity stakes. Twitter is known for it's simplicity. I think this features add more without looking like they've added much at all.

Its also an interesting move towards "app" style, with ajax and less page changes, which is something rather unique in the social network scheme of things.