spister

Gilded for Everflowing is an easy swap.
Reforge for Time Reversal seems right as well.
Ral Zarek could replace that Bolt
Cyclonic Rift is Capsizes newer bigger brother (6 bounce one permanent vs 7 bounce all enemy permanents....as you said, with infinite colored mana, woo! Otherwise, meh)
Dack is an autoinclude. He should be slot 99.
Gotta swap that Hinder for a Force of Will!!
Time warp and crucible seem super strong, either would be better than spelltwine.
Worn powerstone is pretty underpowered compared to the other artifact things you are doing. Doesn't look like your list has room.

First step I think is the lands. Gotta smooth out that manabase to make sure you can always pay for the cards you want to play.
The essentials are of course:
Volcanic Island (yeah yeah, its a bit pricy. But so worth it)
Arid Mesa
Bloodstained Mire
Flooded Strand
Polluted Delta
Wooded Foothills
This will make a huge difference itself. As you begin most games with 1-2 sources of each color.

To expand your two color land cards, you can run:
Reflecting Pool (The best of these in my opinion. Sucks as your only land, but it usually follows a fetch for volcanic)
Mana Confluence (Runner up. Half way between Shivan Reef and City of Brass)
City of Brass (If you need yet another U/R)
Forbidden Orchard (Okay, now we are getting desperate. Scraping the barrel for etb untapped 2 color lands)
Temple of Epiphany (The best of the etb tapped ones, for if you are crazy or something)

Once you have cleaned up the colored mana land friends, you can consider adding more utility fun!
Minamo, School at Water's Edge (Easy add)
Thespian's Stage (Amazing Utility)
Winding Canyons (EOT Nin without commiting to a leyline or something)
Boseiju, Who Shelters All (Potentially useful, but more of a meta call)
Springjack Pasture (Slightly more expensive than kher keep, but only costs colorless and can give you colored mana and life)
Buried Ruin (Academy ruins redundancy)
Desolate Lighthouse (Pretty mana heavy, but a nice thing to do eot while you hold up counters and build your board)
Mirrorpool (Yet to try it, but looks really strong)

If you don't like your friends anymore, you can always double down on strip mine effects!!
Wasteland
Dust Bowl
Ghost Quarter
Tectonic Edge