Oh boy. Maybe we should wait until later in the fall.
We are also just back, and I didn't find it to be all that bad. It helps if you know what to expect. Often, the early am is okay, then there's a period where the heat and humidity build until there's a downpour. After dark and after the downpour, there's a breeze and the temps are often not too bad, IMO.
So summer touring is bit different than other times of year. In winter, the best time to be outdoors is that middle portion of the day. In summer, mid-day is the time you want to avoid the outdoors and take a break.
Yet many people still do the opposite, so you get great park touring during the peripheral park hours. It requires waking up early, but we walked on a number of rides in the AM and at night. After-dark park hours are great.
We lucked out weather wise. We saw some rain, but it was short-lived compared to prior summer tips. Two days we really lucked out, because it rained all around Disney/Universal, somehow missed us, but we still got nice post-rain weather.
One thing we did more of- than prior years- was to drink/consume more electrolytes: water, apple juice, other fruit juice, electrolyte water, dry electrolytes, and chia (seeds).
Another modification is to limit outdoor queues, like BTMRR, esp mid-day. Philarmagic and the indoor character greet queues are great mid-day.
Last, we did Universal mid-trip, and that also worked really well. The staff at the Hard Rock CL were great. We also absolutely LOVED the new Minions cafe and popsicles! The staff could not have been any nicer. Everyone seemed very excited to be working there. A number of patrons even wore Minion colors (yellow and blue).