Though it can be used that way, I don't see the NE as a great controller, last but not least because it is missing Pitch Bend, Mod Wheel and also (even if less important) Aftertouch.
It is strange you didn't find the Novation SL good enough in terms of accuray, I have a different experience (also with an Arturia 61 The Laboratory, not the latest Keylab); in any case when working with Virtual Instruments the velocity curves can (must I'd say) be remapped/corrected on the PC/Mac.
One of the best synth action (imho) on relatively recent models, in my opinion, is still the Motof XS FSX keybed (not so portable, but neither impossible to carry around). Also the Access Virus keybeds, at least from version C to TI2, are very good.
PS: consider also if the problem with velocity is only due to the keyboard or you should try and adapt more your playing style; even on acoustic pianos, pianists don't always find pinos with the same key response, but a good pianist can adapt to any keyboard (to quite a good extent, at least)