would it be possible to introduce a more true newtonian flight model especially in normal flight meaning no "speed wall" just limitless acceleration as it should be in space?
The maximum boost speed [1] has about doubled from 1.0 - it was below 500m/s then, and you can get about 920m/s with an optimised Viper III or similar now.
The problem is that network performance improvements over the last five years have
mainly been in bandwidth, rather than transmission speed, and transmission speed is already pretty close to the speed-of-light limits.
If you're playing in an instance with people in both US and Europe, the distance between the two players is about 7000km (depending on exactly which bits of the continents). The speed of light means you can't get information between them in under 23 milliseconds even if you run a fibre-optic cable directly between their two houses - in practice, the need to have regional and local hubs, and less than speed-of-light network infrastructure means you're going to be a fair bit slower than that. So there-and-back latencies below 100 milliseconds are unlikely to be achievable regardless of advances in network technology.
In 100 milliseconds at 920m/s the Viper III will have travelled 92m. That's a larger distance than its size. Even at more conventional combat speeds of ~550m/s the disagreements between game clients about exactly where the ships are this millisecond can give pretty big issues such as a player dodging a ram on their screen, but getting hit by it anyway because the other player hadn't got the update of their dodge yet, so their client's predicted path was an intersection. (Shadow rams)
The game clients do a pretty good job of smoothing all this out to prevent visible rubber-banding in normal play, but once people are fighting in combat and deliberately being unpredictable in their movements, even the current speeds are probably a little bit too fast for it - and since it's the speed of light that's the real limitation, better networks won't help much.
[1] The SRV does not have a capped speed and people have got those into stable gravitational (i.e. full newtonian) orbits around small moons at about 2500m/s. With a larger body and a higher escape velocity, faster orbits would theoretically be possible.
There's also a trick to accelerate ships to arbitrary speeds when in a gravity well. So the engine doesn't have a problem with ships going that fast
as such - but the networking definitely does.