It was hardly all his fault. I don't begrudge him for taking on the character (we all gotta eat) - I blame the writers for making such a character in the first place. I know that you kind of need a "successor" type character to Indie, since Ford is so old - but at the same time, I think it could have been done a lot better than just shoe-horning in his long lost son, which is, frankly, something a bad soap opera would do.
LaBeouf didn't do a very good job, but I'm convinced that no actor would have. Crystal Skull wasn't bad, except for the last quarter or so where it really dropped the ball, and that's not LaBeouf's fault.
Don't make another Indie Film. Ford is too old, the people involved with making the originals such classics have either left, lost their touch or gone senile, and I just don't see it getting any better from there.
To be very honest, the only thing that comes even close to indiana jones is.... Uncharted 2. Yes, Uncharted 2 is closer to the spirit of Indiana jones than, well, Indiana Jones 4.
Now let's hope to all hell that Uncharted does not become a film.