I love the idea of making minecraft more like terraria! and im pleaseantly suprised by the pack but there are some major issues which if solved could make this one of the best adventure/boss fighting packs that exists.
Firstly, incorporate the boss progression to the main progression.
Some ideas would be to make the boss spawn items in the main progression require items dropped by the bosses in the boss progression,
Another idea is to lock dimensions like the nether and end behind killing certain bosses/collecting certain boss items.
This would require you to kill most of the bosses and would also add a sense of direction as to when you should be fighting the many bosses.
secondly, Make the end eyes craftable similiar to what the chocolate edition pack has done which would go hand in hand with the first suggestion, the eyes would require boss items but could also require other hard to get items forcing you to explore all the mods or atleast some of them.
Lastly, make weapons and armours that are not locked by the armegedon mod locked by some sort of system similair to chocolate edition where almsot all weapons are locked by gamestages to keep a balanced experience.
Im aware this might be alot to ask for and probbably very hard to do, but if youre able to do it this could be one of the best progression modpacks