Item stacking rant

[Taqwus]

Oh, try Late Era R'lyeh on a huge map if you want to be wondering how you're going to feed the hordes...

Think the one case where it's not really clear how multiple items interact would be the (arguably odd...) case of a commander bearing multiple shields. I'm not sure that anybody would ever field a commander with both Aegis and Barrier, but if somebody did, I have no idea how the blocking rules would work.