Cos Dashit character was eventually replaced by Palpatine. However, there is no evidence that Dashit was Force-sensitive like Palpatine.
In the first draft, he is renamed "Son Hhat". He remains otherwise identical in speech and actions.
The novelization of Episode IV originally stated that the Emperor (one of several following the Old Republic) was a puppet. This is implied, though not altogether stated, in the rough draft.
Dashit's first name has caused some fans to believe that Palpatine's full name is "Cos Palpatine". This is fanon. However, a canon character, Palpatine's father and patriarch of the House of Palpatine, was eventually granted a similar name, Cosinga Palpatine.