What would be the future impact of adding too many projects to the blockchain?
Well, you will see just more congested mempool. And then, users will switch into other chains or coins (or even transact with fiat currencies), which on the other hand will decrease this load, and the whole cycle will constantly repeat. It is self-regulating mechanism, just like the mining difficulty.
Are the impacts positive or negative?
It depends. There are some projects with some positive impact, for example sidechains like RSK. Because then, you can experiment with new features, without affecting the main chain. But obviously, there are also other projects with negative impact, for example Ordinals (it is all about data pushing, and the whole "ownership" of satoshis is more or less random, because creators didn't think about things like "signatures" or "sighashes", to do it properly).
Are there no ways to oppose some of these projects before their implementation?
Of course, you can talk with some people, and try to convince them, that some idea is bad, or should be done differently. But many times, people don't listen, and they have to make some mistakes, to see in practice, why their idea is bad. For example, I told them in 2022, that zero satoshis could lead to some problems:
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-February/019985.htmlThe system sounds expensive eventually to cope with approximately 2,100,000,000,000,000 ordinals.
What about zero satoshis? There are transactions, where zero satoshis are created or moved. Typical users cannot do that, but miners can, we currently have such transactions in the blockchain, for example 9f0b871e28fa19e2308e2fa74243bf2dcf23b160754df847d5f1e41aabe499d1 (check the last two inputs).
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-February/019986.htmlWhat about zero satoshis?
A zero satoshi input or output carries no ordinals, so an ordinal index can ignore them.
And here is what happened in 2023:
https://github.com/supertestnet/breaker-of-jpegs