If you destroy all creatures, youre at an advantage in control decks with few to zero creatures, while if youre already ahead on board with small creatures, Armageddon will slow your opponents down, and Caretaker's Talent will help you outpace your opponents while rebounding
Instead, do a little bit of research on Scryfall or EDHREC for alternatives that may fit your new brew better
Sythis, Harvest's Hand will go to deck as soon as I get her
The face commander is Sliver Gravemother, a 5-color Mirror Gallery for slivers that gives them all encore from the graveyard
Magic even has a variety of powerful effects that reward you for paying life, either in one go or over the course of several turns, so you can put the 20 or 40 life you start with to the best possible use
Stronger centering, cleaner edges, and more consistent surface quality give Japanese cards a measurable edge at PSA and CGC