The monument:
I suggested this back when I was testing it, but having little sparkles on the world map for all the levels that secrets were hidden in while the BoS was equipped would have gone a long way in encouraging people to find the secrets on their own rather than outright resorting to the guide. Going through each level on each difficulty is incredibly timeconsuming, when having a blue/orange/red sparkle on a level on the map could have encouraged puzzle solving rather than puzzle hunting. 
Dragons:
They’re big. They’re expensive. They’re… often tragically ignored, because they just can’t keep up in terms of DPS. But there is a clever way to give them a much needed improvement.
Devour. It auto-kills enemies. But what if devour increased stats for the battle as well, making it beneficial to get a dragon out ASAP and also place them in just such a way to maximize their devourings? And more importantly, made them key players in long bonus battles. A few ways it could work.
- Devouring just increases dragon HP or strength.
- Devouring increases random stats, up to potentially infinite.
- Devouring increases random stats, but no higher than *(#) the base stat.
- My personal favorite… each enemy has a fixed attribute it boosts if devoured by a dragon, among the following potential stats.
+RangedATK range.
+PoisonDMG
+PhysicalATK Speed
+RangedATK Speed
+PhysicalATK DMG
+RangedATK DMG
+DEF
+Regen
+HP
+CRIT
+Thorns
Dragon dies or is desummoned? Returned to base stats. 