Interesting ideas.
Turning Sentinel Island into a place which has its own town also sounds like it could be rationalized in the story as well - it's there to foster better human/dragon knight relations so that things like the Slayers don't happen again. I really would like to walk the shores of Sentinel island as master of the tower.
Those people at the Orobas' Tomb- bring'em to the Battle Tower. have them worship you in your very own throne room!
as brought in a current thread- why not have the option to manually equip your runners? yes, on them, enchantments would be moot- unless you deck'em out with Life Line.
more suggestions- stacking/combining charms.