If you would roll one or more dice, instead roll that many dice plus one and ignore the lowest roll.
Whenever you roll one or more dice, put a +1/+1 counter on Wyll.
Choose a Background (You can have a Background as a second commander.)
Wyll turns every die roll into value, growing himself with +1/+1 counters while your roll-altering ability gives you the best outcome on chaotic dice cards. Pick a Background to fill out your strategy, then chain dice-rolling spells, planar dice, and Barbarian/Wild Magic effects to snowball board state. You either ride Wyll as a counter-fueled threat or build wide and explosive around dice payoffs.
Roll-an-extra-die-and-ignore-lowest dramatically improves expected value on all dice effects
Free +1/+1 counters every roll make Wyll a real Voltron threat
Background slot adds flexibility and a second commander's worth of value
Cheap two-mana commander that's easy to recast and protect
Dice payoffs scale hard once you have repeatable rolling engines
Mono-red ceiling: weak interaction, card draw, and recovery from board wipes
Dice strategies can be inconsistent and swingy without enough rollers
Heavily reliant on Wyll being on the battlefield to capture value
Vulnerable to graveyard and counter removal that resets his investment
Limited support pool means decks can feel thin outside dice cards
A repeatable random spell generator that Wyll skews toward better results.
Tighten the dice-roller count so you reliably have something to roll each turn, and add Krark's Thumb-style multipliers (Pixie Guide, Barbarian Class) to compound Wyll's reroll. Improve mono-red's weaknesses with rituals, impulse draw (Reality Chip, Light Up the Stage), and protection like Heroic Intervention proxies in red such as Deflecting Swat. Choose a focused Background that matches your line—aggro counters for Voltron or token support for go-wide—rather than a generic value pick.