Time Rip is definitely a card I would like to add but Aeon Reaver fills the same role of time rip (Aeon Reaver gives you a 4/4 while Time Rip invokes Galakrond and synergies with Veilweaver). Both have their pro's and cons but were going to run time rip then we might as well run all or most of the other invoke cards.
This is not a bad idea, in fact I think it is a great idea because the Priest Galakrond and invoke were greatly buffed as result of the Hall of Fame additions, the new expansion Priest cards, and the rotation of A LOT of bad Priest minions. Unfortunately, even though the invoke cards are powerful and are essentially as good as draw a card, adding these cards would still lower the power level of the deck. This deck is a powerful midrange deck and the individual power level of each card is high enough that we don't need much card draw or card generation. I believe you won't feel like you need more value when playing this deck, and if the case arises where you do, you can easily remove some of the more midrangey options to lean into a more controlling style of deck.
Dragonmaw Overseer is a core card to this deck because we are often going to play a 1,2,3 curve and this is an extremely powerful card on turn 3. It is also not a good draw in the late came if minion combat is still the focus of the game at that point. This card has great synergy with our other early game cards, especially imprisoned hommunculus which awakes on turn three.