keep level low and get money by other means - steamroll level scaled spawns like superhuman.
vs.
focus on non combat skills and suck really hard.
vs.
get high level but no heavy\powerfull ships and rageout.
1. Impossible. There is no way to prevent leveling up; you can not spend your skill points, but you'll still level up. Additionally, this already happened if a player built up a large fleet through non-bounty means; no matter how large your fleet, you'd still start off fighting 3 Mudskipper MkIIs and a Kite (D). This change was made so this scenario you're predicting could happen, won't happen.
2. If you're doing a non-combat build, why are you doing bounties? Surveying, scanning, and scavenging exist now. How many points can you put into non-combat skills anyway, is it even possible to do a dedicated non-combat build?
3. If you got high level through non-bounty means, you can keep doing that while you wait for a "heavy" ship to spawn. If you got high level through doing bounties, the bounties would be scaling anyway, and thus you'd run into this problem anyway.
Additionally, the old system of bounty scaling isn't being removed. As you do bounties, they'll scale up like they did previously. All this does is prevent surveying magnates who want to get into bounty hunting from having to start by killing the aforementioned 3 Mudskippers and a Kite (D) fleet 3 times so the bounties start leveling up.