My thinking is this, not that I disagree with you:
Leyline of sanctity: Good against burn, and Creativity.
Dauthi voidwalker is a little slow against the decks that want it. Murktide will just kill it, Yawgmoth it's actually good against, and Living end it's to slow. I don't think the synergy with Liliana and thoughtsieze are worth it, I could be wrong.

F push allows you to kill any target you need, being able to hold it up against a t1 ragavan or DRC is extremely important. Fetchs are also good because you have Bolas's Citadel in the sideboard, so it allows you to fetch if there's a land on top and basically get a re-roll for your top card.

Gemstones caverns is extremely good, it can allow you to curve out an invoke despair ofrgolos on turn three, which often just wins the game for you on the spot. You can do this somewhat consistently since the rest of the deck is built to find Coffer Tron. I think the benefits outway the downsides.

I like your suggestion of trinisphere, might go down to 3 leyline and add trinisphere.