My two cents as an armchair architect: The Original Gaudi façade is a masterpiece, astonishing to behold in both technical excellence and artistic originality. The sculptural spires are also excellent where they follow the law of weirdness and surprise. The rest is a valiant tribute, but ultimately lacking in the subtlety and freedom of Gaudì himself. It was based on his design as closely as possible, but we can only imagine him re-thinking and warping the design at each stage to create those original details and surprising moments that characterize the works he personally supervised. I found the interior boring, and the newer modernist façade was just an echo of the style in vogue at the time. I would skip going inside next time.
The only reason I can find for anyone to be bored by the inside is if they visited on a cloudy day. The way the light enters through the stained glass and colors the environment (and how the light changes during the day) is astonishing, never experienced something similar tbh.
