Let me say this first: everything I say is from my viewpoint and the way I play chompy.
That change disables his ability to drop his crew, which is his main ability if you ask me. Even if you can still drop chompy for 0 afterwards, it will hugely impact his play-style (or at least the way I play him). I never use that ability as I usually want chompy out with the spell due to extra distance and ability to use another 0 for a spell.
I don't get it. His cache is 0. Yes, he receives a soulstone for each nightmare so it will probably always be 5. But you don't have to play with 5 nightmares. In a build I use I only have 3 nightmares: 2 daydreams and Coppelius.
A dreamer crew is out-activated most of the time. Why make that worse with a smaller crew?