This is subjective IMO, because I actually prefer X4's flight model to Elite's. The big caveat here is that I spent a lot of time customizing my controls and various settings to make X4 as close to Elite as I can (mimicking ED's 6 DoF on my controller). I will grant you that the smallest fighters can feel a bit "light", but the smallest ship I fly these days is a heavy fighter, and I love how it feels. I much prefer X4's version of FA-off to ED's, and I also prefer X4's use of a travel drive over supercruise in ED. Instead of using boost, I mapped the travel drive to my boost button, allowing me to pop in and out of TD while in combat, allowing for some fun high-speed strafing runs. It helps counter these "terminal velocity" limits that almost all space games love to place on us.
If "good" is fun, then for me X4 is better an ED as a 2D space combat game (again, after lots of tuning). If "good" is realistic, then Space Engineers has both of these games beat, though KSP probably is the clear winner (but AFAIK, KSP lacks space combat). All these games are light years ahead of NMS when it comes to flight model.
This is not to say you are wrong - I do understand why many would prefer ED to X4's flight model, I'm just saying it's subjective. Even I had to get used to X4's model (and modify it to be more Elite-like) before it really started to grow on me and eventually replace ED as my favorite.