Maybe a fork brew might explore that more...I do think some broad spectrum counterspell might be useful, if only in the sideboard - your creatures have a goal of entering with some kind of built-in protection, so only a counterspell could offer anything extra
Additionally, the card text of the manga version of "Promotion" mentions the existence of a "Puppet Bishop" (based on the Bishop) and a "Puppet Knight" (based on the Knight), but they never appeared in the manga and have not been released in the OCG
The gameplay was slow to grow on me, given its complexity
Of note, though, you do need to keep a creature around for it to work each turn
The most common way is the suspend mechanic, like on Search for Tomorrow or Sol Talisman, which lets you exile a card from your hand, put some time counters on it, and then cast the card for free when those counters are gone