I remember reading a statement made by Anno in 2006 in which he spoke about the reasons for the 'Rebuild-series':
http://www.animenewsnetwork.com/news/20 ... ion-movies“The desire to connect today's exhausted Japanese animation [industry] to the future.
The desire to fight the continuing trend of stagnation in anime.”
Rebuild of Evangelion, in my opinion, functions as a contemporary take on a 20 year old work of animation. An updated version of Evangelion, meant to connect with a contemporary audience, supplying the current Anime-landscape with a boost in quality.
Aside from that, I have always had tremendous respect for directors that were able to use film as a means to communicate a certain mental state. Anno used Neon Genesis Evangelion in 1995-1997 to do exactly that and is doing it again, with Rebuild of Evangelion, giving us a set of films that communicate a much more updated version of his mental state.
With that said, I think that the films are definitely worth watching, for they are visually overwhelming and will supply you with enough food for thought to compare, analyze and ultimately see Evangelion in a completely different context.
Yet, I have to say that I could very well live without any of the 3 films, because they simply lack the slower-paced, and therefore extremely detailed character development (not to forget: the extremely polarizing effect the cast had on its audience) and highly ambiguous storytelling + nostalgic atmosphere (the original colorpalettes and soundtrack are beyond perfect) of the original series. I can't imagine being only familiar with the 3 films; too many important scenes, quotes and shots are in my opinion absent.
Still, I think that the 3 films are better than 90% of the animation that is being produced today, delivering on Anno's original promise.