Interstellar has some clear influences, yes (way more movies than just 2001 and Contact, btw). I'm not sure how that equates to style over substance though? No movie is wholly original, you're always influenced by something. Not enjoying the film is one thing, but I'm not exactly sure how a movie having some familiar elements automatically translates to a lack of substance. Doesn't seem like a sound argument to me. I see The Right Stuff, Close Encounters, 2001, Contact, Apollo 13...a whole bunch of stuff, but Interstellar is very much its own animal too.
Side note, Interstellar is playing in AMC theaters next Saturday with 12 minutes of additional footage. First time Nolan's ever shown deleted scenes, I think.
https://www.amctheatres.com/movie-news/2015/02/interstellar-imax-encore-buy-one-ticket-get-one-free
Maybe there's a glimmer of hope for an extended TDKR cut down the line?