Good thinker, bad problem solver in graduate school?
Be careful. Interesting conjectures, new ideas are a dime a dozen. The hard work of proving (or disproving) conjectures, and working out the implications of new ideas to see if they turn out useful or are just ephemeral fireworks are the real center of any science.

Just go search in e.g. Wikipedia for conjectures, there are many famous ones (and literally hundreds of less well known ones).