So I looked over Mantic's new Sci Fi Battle rules named Warpath. Given that the rules were written by the designer of 40K 5th edition, it is pretty similar. The rules are simpler which is not a bad thing being only like 16 pages long. Rule complexity should not be confused with tactical complexity.
The player turns are broken up into mainly the same three phases movement, shooting, assault. Movement has essentially stay still, move your base movement then shoot, double movement no shooting(like move+run in 40K but not random amount), or double movement into assault. Since you move into assault during the movement phase the unit being assault is cannot be fired upon. If you have one model from the assaulting unit in assault range of one model from target unit and you unit leader can see the other unit then your whole unit gets to assault. This is because Warpath like Kings of War does not really use model level statistics. Pretty much everything is based on the unit.
Since the game is mainly unit based, you do not remove models to indicate damage. You record the damage taken by the unit and at the end of the phase you make a nerve test against the unit by rolling 2d6 adding damage and subtracting the nerve. If you get a high enough score you will rout the unit or you could just suppress or frag them. You need a net of 10 to break a unit so you will need to inflict nerve + 3 damage total damage to the unit to have a better 50% chance of destroying them. This method of damage is interesting in that you cannot know for sure if you have done enough damage to the unit in the shooting phase to know if it will break since a double one auto passes. This makes dividing your fire in the shooting phase more interesting since you have to decide whether you have done enough damage to a unit to get it to break or not.
In melee, only the attacker fights which seems like a big advantage but if you do not break the unit or score enough damage to frag them (damage markers equal to nerve) they can attack you back the next turn with their full strength or move back and shoot you.
Another interesting difference I noticed was transports do not seem as useful for multiple embark and debarks since it has to be halted the turn people enter and the turn they get out so you cannot move you unit 6 inches to get in the skimmer then move the skimmer 12 inches this turn then another 12 the next turn and then have them get out to reposition the unit like 34 inches in 2 turns. Probably take 3 turns to do that in Warpath.
These differences appear to make the event of the turn seem more simulationous. All moves at once, assaults cannot shoot, shooting final effectiveness not known to all shooting done.
It looks interesting and might be worth a try with some existing models to see how it plays.