It's a complicated question, because it really could be argued either (or even both) ways. Some points you may want to consider:
* He starts out as a very stiff character, so it wouldn't seem out of place that other characters would want to take him down because of this.
* He is extremely ambitious and thinks that Olivia would think to marry him even though he is below her station.
* He is made to look foolish in such a way by Maria and Sir Toby that even the audience feels uncomfortable watching him. We've all been the brunt of others' jokes and made to look socially foolish, it's something we instinctually feel pity for another about.
* His suffering comparatively to a Shakespearean tradegy is fairly minimial, he spends a night in complete darkness rather nobly and never loses sight that he is sane unlike Hamlet for instance.
* But, unlike most Shakespearean comedies, there is no remedy for his suffering. He ends his part of the play by stalking out, snarling, "I’ll be revenged on the whole pack of you," which is unusual in a Shakespearean comedy.
* It can also be argued that he was a sacrificial character - that he was the physical embodiment of propriety and could have no part of the hi jinx that ensued in Twelfth Night so he needed to be put somewhere out of sight for the merry comedy to take place.