Considering power inflation - it is unfortunately not restricted to AD&D...
But Dominions particularly seems to suffer from it less - partly due to patch fixes later (look at Helheim nerfs).
And while I wasn't a big fan of a whole Gath idea (I look up to EA/LA Machaka & Vanarus much more), it turned out fairly good, though very powerful.
As for Eriu & Tir na n'Og - they probably didn't make such big impression due to the fact that idea was present in Dom2 for a time, aren't they?