Yes I'm a fan of the original, no you can't compare them and yes there is so much wrong with the show that it unfortunately outweighs the nostalgia. Firstly, the script is so dumbed down to the point where they have to spell everything out for you. Secondly, I just can't stand the hologram/partner, I don't know why, but she bothers me, she is dull, whiny and makes everything about herself. I don't know why they made her character the romantic interest, it does not make it more interesting.
We also spend a chunk of each episode going over what is happening in real time, outside of the leap. I'm not going to lie, during the original episodes I did wonder what happens in the world that he is missing but the reality is that it doesn't matter, we care about the leap and the main character.
Besides the main character I can't say that I like anyone else in this show, they are annoying and detract from the point of the show, the part that you want to watch. Honestly I can live with the dumbed down dialogue and obvious plots if it had characters and storylines that entertained me, this unfortunately has nothing going for it.
They had a golden opportunity with this show and the stories are basically limitless but they are so underwhelming and they could not have cast the show worse if they actually tried, this is a truly disappointing miss and such a smudge on the name of quantum leap.