They have, repeatedly. This is only the second puzzle they've done in the last four years where any complex code-breaking techniques were required for the answer.
Even then, it's still just "Find key, decode message"... issue being if FD did a more complex, multi-step cipher algorithm, it'd be too much. Even a basic PKI-based one would be pretty heavy-handed.
I'd argue the Coalsack "Stones" messages were harder to decode, though they weren't even encrypted, just scrambled. I guess the problem as well is each time FD do one of these things, that's it. If they committed the cardinal sin of re-using a puzzle technique, a puzzle like this one would be solved in minutes.
I hate to be a broken record, but FD need to lean in to the procedural with this.... this would take a heap of effort, but have some sort of non-broadcast means of collecting bits of a cipher alphabet which can be used to decrypt otherwise innocuous things.... a distributed version of
something like this.
Essentially, it needs to be a parallel activity, not a core activity, otherwise, well, one day FD will run out of puzzle variants.
Its all about self-control, not to look at the specific thread!
There could be a easy to solve puzzle for the majority, that leads to the main goal (narrative/story) and a harder one as extra goal with an extra bonus, like the 750 Mio.
I think you'd still end up with the crowd of people annoyed because it's "content" or "rewards" which were otherwise inaccessible. I mean, take a look at this thread, plenty of people banging on about 750m not being worth it, and 7.5b would be a much better reward (thanks unbalanced economy)... it's a hop-skip-and-jump to start suggesting it should be things like double-engineered rewards instead of "otherwise-meaningless credits". That'd be petrol to the flame.
The only way you can do it is really as an flip of what you suggested; have the main narrative plot plus some relevant reward be the "easy" part, and then have the harder goal as some storyline "fluff" that's interesting to know, but otherwise of no impact.
When I was 15 I moved from Spain (where they didn't teach matrices) to the UK, where they did (fifth form)
Six months later I moved to Australia where I started year 11, and they didn't teach matrices here either.
I think I started learning them from year 9 or 10 here in Australia. Though they were only really covered in advanced/pre-tertiary subjects. You could definitely go through the education system without encountering them... noting for my experience I went through to do Maths/Computer Science majors, and literally[1]
nobody in my comp sci classes knew maths at Uni.
[1] Not literally as in figuratively. Actually literal. Computer Graphics showed that pretty comprehensively...
