allow me to modify some of your ideas and add some more;
- add 15 map key. also add key drop 20% rate on Proelium altar
- key drop rate 100% on boss Oblivious Insula.
- make the drops the same as moon chest and mercury chest combined or in some parts, or added some other low value items. Drop rate need to be different to the chest. (or the 100% key drop on boss OI is attractive enough, 1 hour you can farm 5-6 times, 7 bosses each time = 35-42 keys already.
thumb up for increasing bosses HP on pvp map