Ah my bad for not explaining it well. Having to go into my inventory to use a potion or read a journal interrupts the pacing. Even a simple hot bar like Minecraft could improve the flow, and for picking up journal stuff, you could separate that from the inventory system and then a popup that's like "Press j to read new log" or something, also means players like me wont just throw the papers away afterwards if its separated :)
Also i just remembered, please dont make ESC automatically quit to main menu, when i want to close a menu i instinctively press escape :p