Here's a charitable look at Cage's career. The basic idea is he's a good actor who takes on bad roles because he has money problems. When he's in the right role, his acting skills shine. Roger Ebert explains why he's a good actor here.
If acting only required you to scream and yell at people, then Cage would be the best actor of our time. Too bad acting should require more range than that. It's true Cage had some amazing performances, but that doesn't excuse the fact that a lot of his movies have been objectively bad.
It’s now becoming tiring to see a wretched-looking Nicolas Cage playing a depressed bloke in every movie he’s in, and although his miserable face may be a reflection of his real life circumstances (which includes tax issues and debts) from the audience’s point of view, his films are beginning to congeal into a big gloomy mass; I seriously cannot tell one from the other. These latest filmic atrocities may simply be a string of pot boilers to a debt-ridden Cage, but that doesn’t explain the horrid shite he made during the early noughties since his financial troubles didn’t begin until several years ago. Regardless, the more drivel he appears in, the more his bankability as an Actor is waning, by the time he’s debt free he may never be able to recover from the back-to-back bullshit he’s made.