OK here's my 2 cents.
1. make a great bass with little compromise in quality in it's design point. You reference Sadowsky covering the J bass clones - this means that the company should be aware that a Sad has a market value of $3K and has a great market share in that range.
2. Start with what you have already. this will keep R&D down or at least tooling, materials stock, etc. All contributing to a profit margin or cost savings that the company can afford.
3. find a few respected touring bassists that have a history with Hamer and get their feedback to.
My suggestion:
Well with lakland ditching the Darkstar - you COULD jump back with a short scale Darkstar Newport and Studio.
I think a real niche item - but a solid seller would be a rival to Lakland's Hollowbody.
Your Newport looks like a great platform for a hollowbody bass. Shortscale would make the balance work AND differentiate it.
I think a true large size short scale hollowbody Newport with some of hamer design pickup (ala darkstar, lakland chisonic) and the option for a 4 or 8 string model would be a great offering as a primary bass or a fantastic secondary or studio bass.
Justin Medal-Johnson lists a hollowbody in his "must-haves" for today's bass session work.
then again - revamping the Cruise bass line would be a homerun with the current market. i say do both, who cares is Sadowsky, lakland, fender, Lull, Nordstrand, Aleva-coppola all have successful Jazz similars.
Hamer already has vintage vibe and brand identity in this area.
That maybe enough to shake up a little more market share.
my $.02