Why do you feel the need to clarify your support of Mitt in that manner?
For exactly the same reason that the Republican Party, the National networks, the league of Women Voters and your local Rotary Club sponsor debate forums. To clarify how that candidate performs in a real world situation in front of partisans or skeptical minds as the candidate uses gifts of persuasion to advance a point of view.
This is the essence of leadership, and if your candidate is not persuasive, that candidate is a wasted vote.
There are other reasons as well, which you probably are better at thinking of than me, such as holding a candidate accountable for the things he says.
OH...okay.
Now I see your line of thinking, and I totally agree that we all should see the candidates themselves, if at all possible.
Unfortunately, no one has come to Oregon that I know of, and I believe the local RNC would have let us know if there was an event such as a townhall meeting.
In any case, by the time we have our primary, we might already have our candidate.