Tom Hanks was totally miscast
Firstly his appearance. Walt looked sorta Italian, and Hanks doesn't have those looks. A moustache on Walt made him look classy, on Hanks it looks sleazy.
Secondly, Walt didn't have a southern accent. Hanks totally screws up Walt's "charm" by going into some Southern drawl. Walt had a soft mid-western accent. I didn't even have to look this up to pick it watching the real Walt talk, but I did to be sure and yes, he was from the mid west.
Then there is his acting in general. I'd say Walt may have appeared charming on tv, but like most bosses with their name on the building, they aren't in person. They are driven and to the point. I know they went for the dynamic of everyone being nice Californians and Travis a fish out of water with her British eccentricities, but I never felt like I was seeing the Walt I've read about.