Nerfing devourer stacks for rift herald is the wrong direction
If anything, it should give more stacks. It's harder to kill than drag (significantly), and nobody takes it without there being some sort of bonus. The buff is shitty, and usually it's not worth taking seeing as it';s for pushing, but in reality it mostly wastes time when in that time you could have just taken the tower with the jungler. This will just make the rift herald less relevant.