It has the same playable races/ships as the first game and it does include the expansion.
There are still fighters.
Currently the biggest changes compared to the original are:
* Enjoy better graphics (normal maps, better specular maps, and higher resolution textures)
* Deal with more treaty types (vassals, tributaries, protectorates, and federations)
* Find more component types (plasma cannons, ramming components, etc)
* Experience faster movement and combat
* Interact with randomly generated races (just the young races)
* Discover way more interesting things while exploring
* Protect or exploit primitive races