Liquidation contracts and Arbitrage contracts do check the caller and would not allow to be executed by non-approved senders. This raises the bar, so that you can front run only contracts that you can implement and deploy.
If anyone could just replace an address and execute a profitable transaction by being first on existing contracts, surely miners would be doing it already, no?
Currently incentivisation is not integrated or implemented in Swarm, so a user has no guarantees about what happens with their uploaded content. If the node hosting it disconnects from the network, it will be gone. The plans to address this are through the sw^3 protocols suite and/or erasure coding.
Regarding plain text - it doesn't really matter what bytes you store in Swarm - encryption is implemented and you can store non-encrypted or encrypted bytes, this has nothing to do with incentives for persistent storage.
We try to do outreach and answer community questions when possible, but the team is not big and this is currently done on a best-effort base, we could definitely improve on that front, I agree.
I don't want to hijack the discussion from IPFS, but Swarm has good ideas with respect to dynamic content if you're interested how that might work in a decentralized setting, for example see Swarm Feeds presented here: https://www.youtube.com/watch?v=92PtA5vRMl8
Swarm and IPFS together with Filecoin try to address the same problem - persistent data storage in a decentralised network.
Swarm is not at all "working already" - the incentivisation layer for nodes to store data for other users is not implemented and currently mostly theoretical and work-in-progress.
IPFS is more mature in comparison to Swarm, but the underlying architecture is rather different.
Sorry for the offtopic, but have you ever used TLA+ to verify a non-trivial piece of production software? I recently found out about it, and was wondering if there are good public use-case details on it! I know Amazon has used it for some of their production systems, such as S3, and DynamoDB, but couldn't find many details.