I don't disagree with you, but a lot of those issues are human issues vs technology issues.
There are so many FDMA talkgroups from the SmartZone system hogging channel resources that would be available with TDMA, and some of them are active a lot such as the NJSP on certain sites, or the DEP, etc. The non-public safety talkgroups suck also, however it is worth pointing out that the NJICS started out life as "the DOT system". In fact most of the original simulcast cells are/were named "DOT Cell #" lol