the only suggestion i have, is that some quests have a greater reward than wahat is initially offered.
Nberius' quest nets you a crystal skull that allows you to summon a Creature. Why couldn't it be the same for the "Sibling Rivalry" quest hand get the option to summon a Dragon Elf/Living Armor to your side?

also, the chance to turn the Battle Tower into it's own self-contained town?