You might use Hamlet's own description of Fortinbras and apply it to Hamlet:
a delicate and tender prince
Hamlet describes Fortinbras in this way in his soliloquy in Act 4. Fortinbras in his mission to attack Poland with his thousands of troops seems hardly a delicate and tender prince. The description applies more aptly to Hamlet, who has
a father killed, a mother stained,
Excitements of my reason and my blood
And let all sleep . . .
Hamlet has the motive and will to exact revenge on Claudius, and yet such a mission is very difficult for him. Hamlet's keen sensibilities and insight prevent him from acting rashly. A lesser intellect, a more forceful personality would have plunged headlong into such a mission and perhaps failed just as miserably. But Hamlet wants perfect revenge: he must be sure of Claudius' guilt, he must be certain that Claudius' soul goes to hell, he must convince his mother that he is right.
Hamlet, unlike Fortinbras, is not a warlike individual and is thrust into a situation in which he must act against his tender and delicate nature. He must become what he naturally is not--a killer. This transformation takes its toll of the meditative and melancholy prince.
I assume you want a tag line to describe Hamlet?
I would say, "Hamlet: a man with a plan...kind of."
He knows that he needs to take revenge on his uncle, so first he makes a plan to see if his uncle is really guilty. He tries to get Ophelia to tell him, but just ends up treating her really badly, leading her to kill herself.
Then he has the players act out his father's murder. That goes okay and he does find that his uncle killed his father. After that, the plan goes somewhat off the path he has chosen.
Hamlet cannot seem to bring himself to actually kill his uncle, even when he knows he is guilty. Hamlet tries to stab Claudius, but he does so through a curtain (not the plan) and ends up killing Polonius!
No matter what, Hamlet seems to make a plan, but he can never actually follow through all the way. He is a man with a plan, but it never works out for him and he dies tragically.