I believe German CEOs typically make around 1/3rd of what American CEOs make (having trouble finding the source on that, but that's the number I've seen cited before), possibly in part due to these laws.
Note that there is a difference in corporate management between USA and many european countries, where there is two boards: https://en.wikipedia.org/wiki/Dual_board
The requirement for half representatives for company's employees is for (secondary) supervisory board of directors, not for (primary) management board.
This might be solved by requiring the CEO to not have had any shares. The CEO would focus on continuity of the company, followed by profit of shareholders, both large and small, then.
On the board? Not really unless they're activist investors with some substantial slice of the total shares. The vast majority of shareholders do not actively participate in the compensation decisions of the CEO except perhaps at an essentially superficial approval of the compensation package.
At best one might say a vote against would be to sell the shares, but if public companies broadly all overcompensate their CEOs then it's this tension between leaving most of the market or investing in companies that might make money despite overpaying.
