I've played fives since the late 80's, owned more than a few, and while I can't recommend a brand, I can tell you what I found works , , , for me. This is totally One Man's Opinion from close to 40-odd years experience, Utterly subjective and opinionated.
I prefer 24 frets on a neckthrough instrument. I like having the extra maneuvering room 'up there', and with a neck through, playing 'up there' gets a lot easier:
First, there's no $^*$*@#&*!~~~!~!!!! neck block for the screws on Fender-Shaped-Objects. I HATE those. With a neck through, you have a very smooth transition into the body on the backside.
And Second, there's always a much deeper cutaway on the treble side which helps as well. One of my pet gimmicks is to zoom up there and double a vocal line or lead lick, and that layout makes doing that a breeze. I also love playing bass with acoustic guitars in a no drums setup, and if I need to be an octave up to complement them better, again, much easier to do that. I don't want the bass' backside in my way.
For that neck through axe, I prefer harder/stiffer woods than softer ones: In my experience this helps focus and tighten up the notes, especially in the deep end on the E and B. So timbers like maple, ash, ebony fingerboards, these sorts of hardwoods worked better for me. My first was a Peavey Dyna Bass Five, and that poplar body did me no favors, believe me. The Yamahas were alder which was fine as well. I prefer ebony fingerboards for their hardness and strength, it's like having the fingerboard do the work of stiffening rods. The Alembics ran full 1/4" ebony boards and let's just say the necks were very well behaved. As long as I'm south of 10 lbs. I'm good. String spacing like a Precision is fine. And a flatter than rounder neck profile.
I prefer sealed keys, and a good bridge and Dunlop strap locks. String through the back is a non-starter for me, I don't need one more way to buy the wrong (2 short) strings, and I don't feel much difference to top load.
I prefer active pickups (the real low-impedance ones like EMG or Alembic) and active tone, though bass and treble is enough, I don't need mids. And ALWAYS a balancer instead of individual volumes: I prefer to set the blend then raise or lower output on one knob not two. I'm a big EMG fanboy, I could run them on any and everything I own and be tickled. Great tone, and quiet as a granite block, I HATE electronic noise.
I'm not a big fan of active-electronics-with-a-bypass-switch: These are high-impedance pickups hooked up to a powered tone network. Done right (like the 7-series Yamaha BB's), they're pretty transparent. Poorly considered, you take noisy pickups and amp up the noise. Nope. And I'm not worried about having an EMERGENCY switch to go passive.
9v batteries are NO BIG DEAL. I always changed mine every 4th of July and at Christmas, they were never a problem, and you always take a spare with you. Nothing to it.
I have yet to try a 35" that I could say with no reservations felt and sounded better than a 34" five. I stick with 34" as it offers the most choice for strings.
The 'floppy' B-string is a result of the physics involved to cram that pitch into that scale length, so it is what it is. Do some basses or strings feel 'tighter'?
Sometimes, but never in my experience, again, enough to make me think THAT's the one I got to play. I made my peace with the B-string years ago, and I just play it along with the other four.
I have yet to play a fanned fret instrument, and can see where this could be a great idea, but no experience yet. Yes, strings on a piano harp are different lengths (longer as you go deeper) and is the standard. Does it work on a bass guitar? I'd love to find out.
These are the things I prefer, and hopefully explained why. These things are utterly personal, so I'd urge you to think what would work for YOU.
PS: I prefer a good, padded gig bag to a hard case for non-traveling, no bus, no truck, work.
