I agree. The best that can be said of the compact it that it's an imperfect alternative that's primary advantage is to force an end to the EC.
I would go further and call it unconstitutional and unworkable without a constitutional amendment to eliminate the EC and set up a nationwide voting system.
It's not unconst. The Const gives each state the power to select electors according to it's own state legislature. Basically, the EC had two purposes. 1) To take the direct vote away from citizens so they would not be able to elect a person who would not guarantee the limits on power provided for in the Const and BoR, and 2) not allow the more populated northern colonies/states to band together and elect a regional candidate to rule over all. And that was why the EC had to be based on the racist agreement to count slaves, who had no rights to anything let alone to vote.
There's really no concern now about 1. As for 2, blacks have the franchise now so despite a racist history, the EC is not racist now. So, the only reason for the EC is to make an individual vote in a small state worth more than that in a big state. Imo that's a valid concern, although the exact historical concern of regional disputes is no longer valid. But rural interests are different from urban. There's no reason to dispute that.
But as you posted, just finding a way to proportionally allocate EVs within each state would preserve the good of interest 2, and still more accurately reflect the voters' will in each state. But neither the dems nor the gop will give up any power unless that system actually is better for them than the status quo. And that is not going to happen unless states force it through something like the compact.