@jpnorair, these are very interesting comments. Agreed FHSS with LBT is tricky, though this is not required except for contended access, in which case you can decide on your LBT scheme, as there is on regulatory constraint (except in Japan). I do not think DSSS and LBT work well, especially if you do not want to sacrifize spectrum efficiency and have CDMA-like Multiple Access scheme.
Agreed on channel coding as well, actually Weightless-P does support the rate 1/2, K=7 conv coding found in 802.15.4g OQPSK (as well as Wi-Fi). Concatenation with RS is attractive, it has been considered as well but was left out (of Weightless-P Core Specification v1.0) for complexity reasons. It may be added in a later revision though.
Also agreed on Lora modulation comments, and as it turns out Weightless-P does implement DSSS OQPSK (with limited SF=8 max), again similar to 802.15.4g, except that it is also defined for operation in 12.5kHz channels (while 802.15.4g is 100kHz with 6.25kbps as the lowest datarate. Sensitivity figures are indeed not worse than Lora.
Finally, Weightless-P is TDD (easier downlink/uplink load balancing, open loop power control, etc) and TDMA. Yes, it does require synchronization overhead and a RTC (or equivalent), but that’s quickly compensated as soon as the network really scales, as you have much improved capacity/spectrum efficiency.