I never played morrowind so know very little about Vivek and how he became a Demi/god but has he always been a god or are there/where there people that knew him as a man before achieving CHIM if so then why hasn't he given a more direct route to achieving it then the sermons? Would it be bad for everyone to Achieve it?

People knew he was a mortal before he became a god. The only real question was if he earned it by being awesome, or if he unrightfully stole it through deceit. Most Dunmer thought the former, while the Dissident Priests and Ashlanders believed the latter. But everyone recognizes that Vehk was once a mortal, and replaced Mephala when becoming a god.

He has not always been a demigod. He was a Chimer (what the Dunmer/Dark Elves used to be) until he and two of his fellows used the tools of a Dwemer craftsman named Kagrenac to tap into the power of the Heart of Lorkhan and make themselves godlike figures. This action is what caused Azura to curse the Chimer and make them Dark Elves, with their grey skin and red eyes. Vivec's goal (not sure whether or not Sotha Sil and Almalexia actually shared this goal) was to rule Morrowind as benevolent gods and usher in another golden age for their people.