What if class was to be determined by both economics (exploitation) and power (oppression), therefore in the USSR all the leninist reformists did was to exchange the wealthy upper class for the all powerful upper class. So at best Leninism is a bad reform of capitalism.

No state can ever achieve anything more than the liberation of the capitalist class. The only liberation for the masses is to seek alternative ways to self govern and abolish any centralized power structures from reforming again.