Personally, I never found it "complicated" since I used to code web pages; I create all my posts in HTML, but I did think it a bit "weird" that a 2016 social site would not be all "slick and modern."
My concern was more about what it might mean for "mass adoption;" will those who expect "plug and play" be disappointed and leave. Hopefully not... and I expect true mass adoption is probably 2-3 years out, anyway... so the interface will undergo many changes between now and then.
i am enjoying its simplicity now. facebook is getting way too full of stuff we don't need.