Question, who are these regulars that you're talking about? I don't recall seeing any interviews from Stephen or Grant saying that Tyler was great as Superman. Heck, I can't recall reading Melissa saying anything (not that any of them are obligated to of course).
Well I love being proven wrong. Even when he gets his own show, I will only believe that he has gotten back his mojo once he's treated as Kara's (and everyone else's) equal. In the past, I thought having your own show meant that you would automatically be given some weight to throw around when in the presence of the other stars. However, Legends has proven otherwise for me since the only character that benefited from that show was Kara.lol
Plus, Kara and company are fiercely protected by Marc and Greg. I don't know if they'll allow Superman to share in her spotlight when they've spent several years investing in her character to make her into the bigger icon right now.