I did read the whole thread. No need to get snippy.
I guess we have different definitions of trivial. Using a parsing language to turn json into a associative data structure to determine type doesn't seem all that complicated to me, and assuming the json is well formed (if it isn't there are bigger problems). I'm not sure how this is error prone.
You could just dump the json directly into postgres and query it. You don't really have to touch the data to get it into a time series database. This is simple time series data.
Also, there are not many stats that increase fast enough to worry about failed api calls. Just run an moving average with a short time window and it should cover the gaps.
I have all my stats stored going back 9 months or so and it barely takes up any space.
Most of the non-private stats can be graphed just using the stats page directly in torn, but it is definitely possible to store the data yourself and graph it.
Obviously this only works from when you start collecting data. It would be nice if there was a way to grab a full dump of historical data, even if you were limited to doing so once a day/week/month.
How is deserializing json inconvenient? Every modern language has a library that makes this trivial. I'm not sure piggybacking on HTTP status codes is the best idea in the long run.