They can make content for both platforms in a timely manner without "dismissing" anything so I'm not even sure why that is something you felt you had to point out. Companies do exclusive DLC like this because they get a fat sack of cash from Microsoft, there is no other legitimate reason. As for flying dragons and crazy mod things, many of them could be done on the 360 as is evidenced by the addition of several of them to the base game. The memory limits are more of a problem but that just rules out the more esoteric and visual mods.
Playing: Fallout 4, Warhammer Vermintide Watching: Ash vs Evil Dead