For me the main reason for using PHPtimeseries is to trying to go with the general project direction, as having your own opinion on almost anything, is proving increasingly more difficult. plus I can only offer support on the foum for stuff I have experience with.
Features can get added that only work with officially supported feeds (PHP*) and support for other feed types seems forced at best, as you know we nearly lost mySQL support, the PHPtimeseries seems ok enough to not need to push against the grain, IMO PHPfina is a different kettle of fish though. I wish the project was a little more flexible on this as not everyone needs are the same.
I was actually very interested to see how your suggestion of using influxDB panned out but that got dismissed pretty quickly.