I guess I do not see the point of open carry, except as a political statement. There are too many advantages of concealed carry - like surprising the bad guy and not unnecessarily alarming those who are afraid of guns. As a political statement, that is, asserting your right to bear arms, it has the high probability of back firing onto the "bearers", by alarming the unarmed.
A much more practical and worthy political goal, IMHO, would be to organize a fight to streamline the CCW process in Delaware. It is a disgrace and something a free people should not put up with.
I personally choose to CC as well, and really never OC. I suppose you could say I DO OC on occasion since often when headed to the range I will not cover up, but generally if I ever stop anywhere on the way it's simply to pay at the pump and get gas.
I personally agree with your assessment of the tactical advantages of staying concealed...
On the other hand... The OC crowd do have some good arguments of their own. First and foremost is that they are much less likely to encounter an incident requiring them to use their weapon (and thus the need for the tactical advantage of being unknown) if they make themselves known. Their argument is that most would be BGs will not make their move on someone who they KNOW are armed. Frankly, it's a good point. Us "gun guys and gals" often defend the CC laws by stating that criminals are less likely to act when they know that the population may be carrying weapons. That it doesn't result in bloodbaths in the street, but rather lowered crime rates. So it goes to stand that same argument would stand if they KNEW a person was armed.
For me personally, I think the advantage or disadvantage all depends on what BG you happen to meet, and therefore chance. Some bad guys intent on robbing a store would immediately stand down and move on to another target if they saw a cop inside getting coffee... On the other hand, another BG just might get behind the cop and take him out first knowing he was the real threat. It can go either way all depending on the state of mind.
For that reason, I personally feel that CC offers the best choice for me. In the latter case above, I'm not a threat so I don't have that to worry about. On the other hand, while I may not "prevent" it from taking place to begin with, at least then it's MY CHOICE as to rather to act on it or not. The advantage is mine as well as the choice.
However, for all the reasons and more above, I don't believe one choice or another is the "right" choice for everyone.. I think it's up to the individual (as it should be) and ultimately it's what makes them feel the most safe.