Mary Shelley, in writing Frankenstein, used the character of Walton as a plot device to help convey the story of Victor Frankenstein, while also adding drama to a story not already lacking in it. As such, Walton is a character who finds himself in a life-threatening situation of his own making. In that sense, he is not particularly sympathetic. Like the mountain climber who ascends beyond his capability, or the hiker who gets lost, Walton's predicament is a matter of his own decisionmaking and, consequently, his situation is unfortunate mainly for the fate that may befall his crew.
Walton embarks on an adventure largely out of boredom and a need to achieve something worthwhile. The following lengthy quote illustrates his mindset:
"I may there discover the wondrous power which attracts the needle; and may regulate a thousand celestial observations, that require only this voyage to render their seeming eccentricities consistent for ever. I shall satiate my ardent curiousity with a sight of a part of the world never before visited, and may tread a land never before imprinted by the foot of man."
Frankenstein begins and ends with Walton on board the ship he chartered to explore unseen worlds. The innocent and irresponsible enthusiasm that was earlier reflected in his letters is replaced by despondency and fear as his ship remains threatened by ice flows and his crew growing mutinous:
"The die is cast; I have consented to return, if we are not destroyed. Thus are my hopes blasted by cowardice and indecision; I come back ignorant and disappointed. It requires more philosophy than I possess, to bear this injustice with patience."
Walton is arrogant and, quite possibly, foolish in his expectations that his crew continue to risk their lives for some ill-defined purpose. As such, he is not worthy of sympathy. As an explorer and the conveyor Victor Frankenstein's macabre story, he is worthy a little sympathy, but his delight in Frankenstein's company aboard the ship is born of arrogance. He is elitist, and disdainful of his crew's fears. On balance, he and I would not likely be found in each other's company.