Is this 45mm omega seamaster planet ocean too big for my wrist?

It looks good to me.

For me a watch’s size is only one component of the overall experience. I have large watches that make sense to me for a variety of reasons (dial configuration, information presented on the dial/bezel, unique colors/patterns, etc) In this case I like the overall look of the watch especially with the orange bezel and the size of the watch probably helps emphasize the overall look.

No.