Not sure how my post which literally opens with discussion of the monarch mechanic is disregarding monarch?
My point was that this card is a bit of a win-more card. If you have sufficient blockers (which probably means you are already ahead on board) before you resolve this on turn 3-4, you will probably win having gotten 2 cards and a 4/4 angel for 2WW by the end of your next turn (in addition to your other spells) with further value to come for no additional investment. If you draw this later when behind on board or can't drop this on turn 3-4 without losing monarch, the spirit tokens don't make up for giving your opponent additional cards and they can't attack until two turns later meaning your opponent could net multiple cards before you reclaim monarch. In sum, if you're ahead on board this will often close out the game. If you're behind on board this isn't particularly good. I may test this yet, but as stated I have reservations.
I agree that Palace Jailer is extremely good. If I can get even a couple other cubeable monarch cards from this set or a future set, Jailer will go in along with those cards. I want at least a little interaction with Monarch though (besides stealing it via combat damage), I don't want Jailer to be the only cubeable card that grants this ability.
I think the issue is assuming that "sufficient blockers" = "ahead on board". If your opponent has a pair of 3/3's, and you've got 2 2/1's, you're definitely not "ahead on board"... but you do have enough blockers to hold onto the monarchy for a turn, and start outclassing their dudes with angels. There's going to be a lot of situations where this can turn one turn of chump blocking into a tide of advantage that keeps it from being relegated entirely to "win more".