izigame.me

Overall recommendation: wait for patch notes with significant buffs or reworks to the character.
Current State: 2/5
Kit seems very confused and underwhelming. I'm not really motivated by defensive scout builds as there are plenty of tanks in the game. This leaves speed and fury. I've tried a speed build, but it's severely hampered by losing "fast" at the start of your turn. This means that allies can't buff your speed to set you up for a powerful turn. In order to get ramping you need to play a non-trivial number of melee cards (or skill cards), but it's difficult to work in enough draw and energy to make it significant compared to other heroes that can more quickly stack buffs like sharp. Plus if you didn't start with a big ranged attack in your hand at the start of your turn, your potential is so much less even if you have draw due to the base energy cost. There is some synergy with stealth since those cards also tend to add fast and it can boost your damage before playing the ranged attack for your turn, but again, where's your energy coming from? Can you build enough fast stacks on a single turn?
Right now the only thing that seems viable to me is building a deck of primarily Sprint, a few Shadowstep, a few Burning Shot and Explosive Shot, and Setup with the intention of starting with 1-2 ranged attacks in hand along with your setups, then drawing as many sprints as you can in the turn. With the reduced ranged attack cost, your primary energy cost will be the Setups since the Sprints are free. Maybe the best way a teammate could contribute is by giving you an absurd amount of inspire so you can forgo the Setups and stack your deck with Sprints and work in a few Hit and Run with the leftover energy. A healer with Scry or Fortune Telling can be very useful to make sure your turn isn't a complete dud.

My recommended changes:
Character:
- Make the Character passive that speed can stack and one of:
A: Lose X% of fast stacks at the end of your turn
B: Ranged attacks consume X% of fast to do a corresponding amount of damage
- Early Perk: "Ranged attacks cost 2 less energy, you may only play 2 ranged attacks per turn"
- Add a final-level perk that removes or reduces the loss of fast stacks
- Rework Rocket boots (due to character passive change, just make this a fast-boosting item)
Cards:
- Base "Hit and Run": 0 cost for 30% of speed slash and one fast stack, upgrade paths:
A: 2 energy for 100% of speed and one fast stack
B: 1 energy for 50% of speed and 2 fast stacks

Theme: 4/5
As for thematic, I like the ability of the engineer being a scout that has flame attack options. However I feel like the kit would look much better if the build decision chose between ramping power over time - "improvements" so that later turns build towards large amounts of damage - and either an up-front consistent amount of damage / utility to have impact while other ramping members of the team are building up their stacks (which the speed build seems to supply since it's mostly self-sufficient).
Maybe for ramping, that's where the fury path could go. And to switch things up, have rage add burn stacks instead of bleed as that gives more control for the team and fits thematically.

One other idea that came from thinking through the defensive build with a friend:
Character passive: "Engine"
Fast is converted to shield at the end of the turn, block at the end of the round is converted to fast (before shield is converted to block).
This creates a 3-turn cycle between fast, shield, and block. Nenukil could choose whether to constantly build all cycles of the engine by focusing on a single stat (speed or block)
OR alternate stat focus to stack a single cycle for a large future turn. This would also provide more opportunities for team synergy (Ottis, Heiner, etc.) and provide an interesting but still thematic puzzle for more advanced players on how to get the most out of his kit.