I thought that "Σmerald" would have been the best.
Sigma? really Sigma?
I don't agree by a long shot.
Omega Ruby and Alpha Sapphire were likely chosen as XY are emglish Alphabet and the Hoenn Region shares a lot of themes with Kalos, and they wanted a Alphbetic name scheme to use but no repeat English Letters
There's also the extreme cultural symbolisims:
Water supports and therefore cradles life, a begining so to spak, Hence Alpha Sapphire //wheras// Lava and quakes destroy and ruin lives, Hence Omega Ruby.
That plus Sapphire in the manga was the girl, women often are considered the cradles of life in popular culture, whereas men are takers of life within those same cultural references.
Alpha(the beginning, giver of life) & Omega(the ending, taker of life) are the theme here...
So ultimately, Sigma, as well as any other Greek letter, has no true place within this theme
However I do like the thought of Delta Emerald
Delta is represented in greek letters by a triangle, this triangle shape could hint at the fact that Kyorge Groudon and Rayquaza are a trinity rather than a pair between Kyorge and Groudon.
These three legendaries take some influence from the tales of Leviathan(kyorge) Behemoth(Groudon) and Ziz(Rayquaza), the Hebrew mythologic beasts of Water, Land and Air said to be unconquerable by men.
Even so, the fact that past remakes have been in pair-only format can be overlooked for the same reason as my earlier skepitcism: The Past 6 games(BW/B2/W2/XY) have broken the "Pokemon Mold", so who knows, we may(based on mold-breaking history {aka the hope for the best}) or may not(based on past actions {aka the expect the worst}) get Delta Emerald.
My opinion on whether or not to make Delta Emearld? None yet, I wanna try ORAS first.