In what specific ways would you like him to be a better ruler? I mean it's a bit fuzzy to me why people considered him a bad ruler to start with other than him being a puppet of a foreign intervention. And Polish troops were necessary for his reign, with or without Marina.
Finally, his legitimacy was in claiming to the Dmitri Ioannovich, so he wouldn't be starting a "new" dynasty but claiming to be continuing the Rurikid line.