Ethereum

There are a lot of debates around native rollups;

My first concern is whether we are reinventing sharding again and if this approach has the same problems that made us to revert sharding from Ethereum's roadmap. 

Trying to give answers for this.

So, the answer here is yes. It is similar to sharding, but at least we know how to do it. We have a better research guard, and we know how to do it by creating an open market.

The second question for native rollups; 

Isn't it introducing new systematic risks to Ethereum's social consensus? Similar to what happens when we try to unfreeze the bridge via an L1 soft fork, also be said that we should trust L1 for possible L2 bugs.