1. Earlier guardians were up to level 6. Getting a level 1-3 adventurer would help upgrading to a level 4 guardian. Players would only upgrade to level 5 and then level 6.
Now we have till level 8. Going by same logic, a level 1-3 adventurer is hardly much of a help with progress. Getting a level 4 or 5 adventurer will help in achieving level 8 better. I feel the rewards should now be proportional to the goal.
Other rewards like Guardian Pass, 3 holy bonds for 1 grade 5 guardian, etc have improved rewards from level 4/5 guardians to level 6. Coalition arena seems to be lagging behind.
2. Any time a bond is opened, most probable case is a level 1 guardian. That makes a level 1 adventurer value pretty insignificant. Since we can't get more than level 3 guardians from bonds, it would be nice to have the opportunity of level 4 and 5 guardians from COA arena.