In terms of being unnecessarily hard to program, that was the Saturn. Which Sega learned from and made the Dreamcast relatively easy to program. They just chose

In terms of being unnecessarily hard to program, that was the Saturn. Which Sega learned from and made the Dreamcast relatively easy to program. They just chose the a newer revision of the CPU architecture they used in the Saturn, which wasn't a terrible choice. Interestingly, developers complained about the N64's difficulty too, so Nintendo also made the GameCube easier to program. Which just goes to show that a console's success has little to do with how easy it is to program.