not sure if this is the right place to put this, but most of the "Edain Mod Feedback", I think, would be for serious discussion about the mod, and this is, well, more silly.
It seems to me that the modders created Mornamarth so that fans would be forced to use the most popular pronunciation of the Sindarin word "Amarth".
As a metal-head, I see this a lot. The Swedish death metal band Amon Amarth is often pronounced amOn amArth (the large, capitalized letters indicating where the syllable emphasis lies), even though I've never heard Amon Sul pronounced amOnsool. I've always pronounced it Amon sUl and Amon Amarth, with the syllabic emphasis on the first vowel unless there is any indication otherwise.
But with Mornamarth, it sounds odd to pronounce his name mornAmarth, as I usually would. But the popular pronunciation of Amon Amarth (as listed above) would make pronouncing his name "simpler", since it would be mOrnamArth or mOrnamarth.
I'll show myself out, thank you, but not after taking the etymology nerd of 2016 award with me. At least Professor Tolkien would be proud of me, lol.