I found this kind of odd since it only prevented me for building Diseased Corpse's until I had all four of my Eidolons.

's because they can upgrade to them, and the mechanic of national units isn't in vanilla so it never came up. It can be fixed by adding an upgrade for diseased corpses to SNAITM so they never obsolete - that's what he's there for!

It would be better to set the <bNeverObsolete>1</bNeverObsolete> instead of <bNeverObsolete>0</bNeverObsolete>.

I personally think that all UUs and units that upgrade only to national units should have this.

I was too lazy to go though every unit though, so I just used replace all. I don't really have a problem with the longer lists of units I could build.

That and "Sir Not Appearing in the Mod" was removed on the switch to BtS, mainly due to the addition of the <bNeverObsolete> tag I imagine.

Good point - I may be a little out of date there!