Theres a good chance you wouldnt want to use her in challenges anyway, because she comes packing a massive three lore to help speed you towards victory
This is Simic value dialed beyond busted, into shred the design file territory
Rather than an expensive ultimate you'll never get to use, Elspeth has three cheap and useful abilities
Urza, Lord High Artificer Urza, Lord High Artificer was the first card to depict the ancient well-known planeswalker on his own
(Choose any number of permanents and/or players, then give each another counter of each kind already there.) Illustrated by Dave Kendall Standard Not Legal Alchemy Not Legal Pioneer Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
Theres certainly bigger and more explosive changes you can make to a deck like this, but these changes keep to the spirit of what was originally there, keep the deck at a similar but more resilient power level, and, importantly, clock in at under $25 (as of the time of this writing)