Are you so fanatical that you refuse to learn new information? No, you cannot limit arbitrary data, because Bitcoin *is* data.
1. The datacarrier size field for OP_RETURN data is and always has been a setting that users of the client software can change. The default setting was 83, and as of v30 it is 100000. Users (of any version) can change it to 83 if they want. Or 300000. Or whatever. It is up to the user. Only the default value changed.
2. If by "removed the filter" you mean the option to relay transactions with arbitrary data, you are wrong - the option is still there in v30. I just verified on my node.
3. The client software (there are several available) merely relays transactions from the mempool, it does not control what miners can include in blocks. Miners can use any client software they want, with any settings they want, and are incentivized to compose blocks with the highest fees. Once valid blocks are added, all nodes will add them to their copy of the chain.
4. The BitMex article that you refuse to read proves that spam can be stored in *any* area, even private keys. We cannot ban private keys. Ergo, we cannot ban spam. It is a moot discussion, because Bitcoin is made of data, and therefore data can be stored in Bitcoin. Get over it.
So the question is one of incentives: do we want to incentivize storing of arbitrary data in a non-essential field that can be pruned, or in non-prunable, essential fields like UTXOs? You seem to want permanent spam instead of prunable spam.
As weak as client settings are for incentivizing, maybe it will make a difference in the long run to suggest a prunable field for arbitrary data, so that nodes can choose a smaller data footprint by enabling the pruning option. Unfortunately inscriptions have already been invented, so the technology is available for storing data across UTXOs, permanently.
I'll never understand how people become so enamoured with drama queen narcissist losers like Roger and Luke, who revel in the attention they get from their stupid, ill-advised causes. Restricting data sizes willy-nilly out of blind spite for spam *will* break functionality for important technology like the Lightning network, and complex signature structures that will be important for business operations in the future. Let's not throw the baby out with the bathwater, and undermine confidence in Bitcoin, just as it is becoming part of the global financial system.