(Changing the mem and arts usually requires a shareholder meeting, and can be contested in court if the interests of minority stock holders are not taken sufficiently into consideration.)
In addition even if you do hold stock of the same class as the founders that won't always prevent you getting screwed over. The board might sign up to a sucky deal through innocence, incompetence or collusion and condemn you as a side effect.
Remember, this is all at-will employment - either of you can end the relationship at any time. This is where an equity grant/option with cliff vesting comes in. 4 yrs with a 1yr cliff is fairly standard... In other words, if you get fired or leave before 1 yr, you don't get that equity/option and it reverts to the company.