There's lots of good info in here already, so I'll just add a few thoughts that come to mind...
I lived my first 20ish years in WNY, and have been a full-time Floridian another 20ish years after moving. I have NO regrets! I'm in the Tampa Bay area, about 5 miles from the Gulf of MX. I absolutely traded 3-4 months of hibernating from the cold for 3-4 months of hibernating from the heat, but it's a trade I'm happy to have made.
FL has several different climate zones: way up north, it can get very cold in winter but still hot in summer; mid-FL is considered sub-tropical and we don't get very cold in winter, though we have the occasional dips into the 30s, and we also get very hot in summer; and south FL stays warm year-round because cold fronts rarely reach that far south, and it, too, is very hot in summer. On top of that, inland vs. coastal can be quite different. I live on the Gulf coast on a peninsula, with the Gulf on one side and Tampa Bay on the other - this acts like a bubble in late summer, trapping heat and humidity overnight, so our "lows" rarely drop below 80. When I've visited Orlando (inland) in August/Sept, I'm always amazed by how much more comfortable the evenings and mornings feel. But Orlando also gets hotter in the day than my area and doesn't have the sea breeze I get at home. I imagine there are subtleties like this all over FL.
You mentioned wanting to be near both beach and WDW, and I want to explain how that is difficult. Like I said, I live 5 miles from the Gulf, but traffic in FL in general, and my area especially, is HORRENDOUS. Right now, in peak tourist season, it can take me 30-45 minutes to get to the beach. Then I have to find a parking space, along with thousands of others trying to do the same. Biking would be easier, but we also have a pretty ugly record of cyclist-motorist accidents. I live 4 miles from work, but it takes me 45 minutes to get home this time of year - only 15 in the off-season (summer.) I put up with it because living near the water is that important to me. If I lived inland, I'd probably never go to the beach. WDW is an hour and 20 minutes away on a good day, 4-5 hours on a very bad day. It all depends on what's happening on the Interstates. I will never, EVER again go to WDW on a Friday, in rush hour, during a thunderstorm, lol!
The threat of hurricanes is real and something you either learn to live with, or move away from. There is no part of FL immune to their destructive power. In coastal areas, storm surge and flooding can be a big problem, in addition to damaging winds. Inland, wind speeds may decrease a bit, but can still produce plenty of damage on their own and from spawning tornadoes. It's critical to know your evacuation zone and have a plan for when a storm comes along.
Those of us who moved and never looked back are willing to take the negatives because FL is so rich in beauty and warmth! Every gorgeous, warm, sunny day in February, I'm happy I made the move.