Pretty neat idea but the unstoppable would just become more unstoppable…
I think that this would be more of an equalizer because the bigger you are the more vulnerable you are.
Speaking of equalizers, I think this idea has an added benefit of making less valuable systems worth dwelling in. If a hostile alliance wants to harm another alliance on the systemic scale, it’d be natural to target all the -1 and -0.9 systems. So, people move into the -0.5s and -0.4s. Maybe living in a pipe become worth it again which leaves you susceptible to ganks.