Just came up with some food for thought: both the WDWRR and TTA operate out in the FL heat and humidity without onboard air conditioning. I do admit both receive a bit more shade/cover from sunlight than the gondolas will offer, that they are completely open air vs louvered reflective windows, and that the TTA does run through buildings with A/C, but these are "low-speed" transport methods out in the FL sun that we typically don't hear a lot of complaining about.
Basically what I'm saying is that it's entirely plausible that the "OMG NO A/C?!?" crowd is making a mountain out of a molehill. Time will tell.