Trying to dail in the NS2A I picked up and I realized I will have to raise the action a bit. I think I'm a little heavy handed I guess. It also has a lot more high end than my Legend 5 with a haz copy pre. I'm not sure if this is a result of the P/J pick-ups compared to the DC's of the Legend or the pre's and or both. Both basses tone controls have center detents and the Legend I run pretty close to the middle( about 55% of both). The NS2A I have the bass abot 80% and the treble around 35%. Anyone have any thoughts on this?
Just my opinion (and I'm assuming you have a Haz copy in the NS-2A as well), but it's probably mostly the pickups and how they are interacting with the Haz based on their intended tonal footprint as designed by EMG.
The preamps that EMG installs inside it's pickups (be they CSs, DCs, PJs, Alnicos, JVs, MMs, etc.) are all the same. The only different internal preamp they've got is in the X series, so unless you're comparing those with the regular EMGs, you're dealing with the same internal pickup preamps.
However, The way the coils are wrapped in EMGs (and this is across their models) differ to get the desired tonal footprint. 40DC humbuckers tend to have a more detailed and crispy high end than the P or the J, and the MM pickups are wrapped differently to get that Music Man tone.
Unless you have drastically different Haz copies in each bass (like someone replaced the pots, or they are different model years or something like that), it's just the way the pickups are interacting with the preamp. Again, this is just my opinion from my experience using EMGs. A good example: When I had Chuckles' LX5 with 40DCs and the smadder setup and the Ian Hill with regular EMG PJs and the smadder setup (before I put the X series in them), the humbuckers had a lot more high end than the PJs. You could even tell when everything was set flat. So in my opinion, you're just dealing with different tones because the pickups vary both in design and what the frequency response is for them. I doubt there's anything wrong with the Haz copies themselves.
And I'm in the same boat as you. I want the action as low as possible, but I'm a heavy right hander, so I have to end up settling for medium low action. When I was at Jaymi's delivering the Ian Hill, he lowered it and I had a really difficult time playing it because I pluck so hard with my right hand. Same when I tried his Wimbish. It really threw me off. So I'm thinking about consciously trying to change my plucking style, but at heart, as much as I love playing neo-soul, hip hop and funk stuff (which is the bulk of what I get asked for), I was weaned on rock and it's hard to unlearn how my right hand attacks the strings. But my left hand loves the feel and ease of super low action setups, I just need to think about if I want to make a decision to consciously change my right hand attack or just stick with what I've been doing for years. It really would take a lot of work to change it because instead of thinking about the music, I'd be thinking about my right hand, you know what I mean?
I wish I could have the best of both, but physics just won't cooperate with my desires

.
Sorry if I rambled a bit, but I hope this helps.