The second change seems anodyne enough, but the first significantly changes Luke’s motivation IMO since he now decides to become a Jedi without any information about his father’s wishes. Because of this, the revelation in ESB could have less of an impact because Luke is becoming a Jedi more of his own volition and less because he believed that his father wanted him to follow in his footsteps.
I agree it would change the characterization, but not by much. Either way he’s deciding to follow in his father’s footsteps. One it’s due to his father’s wishes, the other it’s him actively wanting to be like his father (in absence of knowing his father’s thoughts on the matter). Depending on how you look at it, the latter could actually be more devastating in regards to the ESB reveal. I don’t think it’s a problematic change at all (the alternative, if you’re considering the prequels canon, is a far more severe character change for Obi-wan).