You'll get used to the heat if you don't use the aircon. I never gotten used to the winter in germany though. As a kid I didn't mind but as an adult it got worse every year.
Germany during summer is kinda nice, but its only 3 out of 12 months.
Discussion
I like wearing wool, so I actually don't mind the cold. The dark bothers me, but we just take a winter trip to the Mediterranian and retank.
Germany = EU+Schengen, so you aren't tied down. Can move around easily, too, or have a vacation home in Portugal, or whatnot.
We're just talking about primary residence.