The downsides of the new serialization is that it's more computationally expensive to decode than the traditional one, and of course the implementation has a bit of complexity.
I'm curious about this part,
1. Is it right to assume computational power to encode the data more/less same with current serialization format?
2. Are there any less rough estimate of "more computationally expensive" on decode part? 20%? 50%? twice?
IMO 15% reduction in the total ongoing bandwidth usage is big deal for public node with hundred connection.