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The linked mail talks about XTS constructions, so the thread is about block encryption commonly used in disk encryption schemes. They also mention that they'd have to handroll such a scheme with ChaCha. I assume that Speck offers a native wide block mode which would make a better candidate for software disk encryption if it weren't for the backdoor concerns.

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That is fair, but that is by no means an argument for Speck, but instead just an argument for a block mode cipher.

What they would need to do would be to find a different sensible block mode cipher, rolling a cipher-text stealing operation mode like XTS for a stream cipher (which is not that complicated, although one should do their homework first), or using a construct to convert a stream cipher to a block mode cipher so it can use XTS directly (which is possible, but care must be taken).

#2 would probably be best. I am not sure if it a trend, but I seem to mostly see new stream ciphers popping up, so this solution is likely more sensible.

We have a stream cipher based proposal, but it's a much bigger change and needs much more review, so it can't be landed for P. A drop-in replacement for AES is a much simpler change to make.

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