Too much dialog written in the most obvious fashion. Too little mystery. Too little tension. The essential drama and motivation of the story missing as much as No. 6's mind.
The issues with this series have less to do with its similarity or non-similarity to its source material than it has with the tenor of contemporary film-making and writing. Classicism and all its artistic forms have all but disappeared from education, so it is not surprising that what passes off as entertainment today is hardly groundbreaking or even interesting. There are exceptions to the rule, of course, but by and large episodic television is at a low point.
It isn't even so much that Prisoner 2.0 differs from the original (in itself not necessarily a bad thing if handled properly) but the fact there is little personality to the proceedings is its major weakness.
Film-making, collaborative or auteur, rely on the singular voice of its many artists ringing out in concert, guided by the deliberate hand of a producer or director who sees the forest for the trees. Film-making is about style as much as about content and the two have to cohere meaningfully. When it doesn't, as in this new reboot, the results are muddled.
The presence of Ian McKellen isn't enough to elevate it and Caviezel simply miscast.
Too bad.