I keep trying to make fleets using this 7/1 engine but no matter what configurations of corvettes, destroyers and frigates I use, I simply cannot justify the relatively small gain but the huge penalty of running out of Olzyl and being dead in space at warp 1 over the superior 5/3 engine.
Is there a use case, other than early game and maybe colonizers, to use this extremely niche engine?
I think not and not having an option for 5/3 engines makes end game a bit dull. So I suggest increasing the lower warp speed to 2 so it comes 7/2 and make it more fuel efficient. That way it is +40% faster than 5/3, at max warp, and -33% slower at min. warp. Much more balanced than the current +40% and a massive -68% slower as it is now at min warp. This way you actually have options for engines.
This will also give a bonus for smaller ship fleets as they are the only one’s that can realistically use the 7/1 engines.