I hadn't noticed how stiff the stick was on my original DC controller until I recently played with my other one, which is extremely smooth in comparison. I noticed this Reddit thread about the issue, with the advice to use some synthetic lubricant on the plastic components beneath the stick: https://www.reddit.com/r/dreamcast/comm ... ick_stiff/.
However, after disassembling the controller and lightly applying lubricant to the mentioned plastic parts, it doesn't seem to have made any difference. Has anyone else experienced something similar or had luck with any other method to clean/improve the analog stick mobility?