Do I support the Electoral College? in a word, yes.

I believe you are using the wrong metrics. It makes no difference what states candidates visit. If Montana has more electoral votes than it "deserves," then the EC serves the rural voters there, full stop. If a party adopts a rural strategy, its candidate can just say so without visiting the states.

Your focus on slavery is misplaced. The issue was the population density of agriculture vs. industry and finance. If there had been no slavery, the rural states would still have had people working on the plantations, and those people would have counted. It's the two-senators-per-state rule that skews the EC. References to slavery rile people up, but they have nothing to do with the desirability of the EC.

Swing states save time and money and effort. I live in a safe state right next to a swing state. I am comfortable that the candidates who are seeking the votes of people "like me" in the swing state are representing my interests well enough.

And the pact is just plain silly. It's all blue states. No red state will join, and no swing state will surrender its swing status to join (unless its state house and legislature is captured by the Democrats). The first time any state would have to give its electoral votes contrariwise to the vote in the state, the thing would collapse. (I doubt it would not be legally enforceable if a state reneged.)