A lot of great suggestions! They will be considered! You can join the Discord too if you want to discuss further with other contributors!
In the original GameJam build, status effects slowly decreased over time. Each turn, all effects would go down by 1. This seemed like a good system, but it lead to confusion for some players. A lot of effects are added passively each turn. And it can be confusing to have your haste go up by 2, and then the next turn go down by 1, and then up by 2 again, giving you a total of 3 haste on your second turn. A lot of players were confused by this - so we removed it. I agree that it makes status effects overpowered now. Not sure the correct solution yet, but we're thinking about it! Maybe they just need to be less common. Status effects can be removed using the Cleansing Potion and Cleansing Bomb.
As for the curses, I do believe the new system is a lot better. It forces the player to reorganize and lose their "perfect" setup, forcing them to make sacrifices and hard choices. The real purpose of the "curses" is to get you thinking about your backpack layout - so just having them on-top of your items often didn't achieve this and it just became another way to inflict damage on the player. I totally understand your criticism though... maybe we will find a way to improve them further.
As for the balance issues, you're 100% right. Poison is overpowered. Magic is overpowered. These will be addressed in updates!