One of the problems the needle guns had was that the needles had a number of problems. One of those was in metallurgy of the day, and other was in the corrosive nature of combusting powder. Those are slightly better today. But, the problem of mechanical reliability of a very long and slender needle firing pin in a hot gas environment remains.
The fact that you have a needle projecting out of the (presumably) rear of the chamber brings us back to obturation issues. Desn't mean it can't work. Just would probably need a bunch of steps. Like moulding a hole through the propellant to guide the needle. Probably a teflon-coated titanium needle, too (not sure that would have enough reliable mass for a 60-75mm stroke, though).
And, it's entirely true that a primer need not be centered. Other than, it's significantly easier to mass produce items that are co-centric, particularly when you are planing on making said item in tens or hundreds of thousands. There's a different issue in that needing to align eccentric items that are round gets complicated quickly.
It's a fascinating engineering exercise, and really, the more out of the box, the better. I was gabbing with a cohort the other day and a musing occurred--why not a ring primer? What we worked out was that this would probably be best with a gyrojet-style loading cycle, where you slam the round backwards into a closed chamber. Which would get to regulatory issues, as that's really an open bolt.
All sorts of ideas out there.