I also like the ideas here a lot.
One thing though. Is the "thresshold rule texts" supposed to be abilities or triggers? As it stands now it seems like they want to be both. Since they are all at the start of your turn I'd make them triggers.
You don´t need to write:
COST - At the start of your turn...
You have to pay: At start of your turn, you may... ...if you do...
Start of Turn Triggers.
But this is far to mighty. For 4 put something back into hand. And AFTER THIS you can detach...