There are so many loving plot holes in HL it's not even funny
Like seriously how does one man manage to survive against a force that caused the military forces of the ENTIRE loving PLANET to surrender in a suit not designed for combat, as well as no actual weapon training (picking up a gun in HL1 does not count as actual weapon training, mind you)
Also, yes, I'd like to see what happened during the seven hour war, I'm pretty sure there's a mod floating around on Steam Greenlight for the events after the seven hour war as well.
However, I'd love to see a continuation of HL2's story, rather than just a "And now for something completely different"
Seriously I'd rather have some sort of resolution to the whole "Combine all over find Borealis use whatever's on the Borealis and use to explode Combine"
But it was executed so much better, there was an actual reason behind it. Why did combines even invade?
Pretty sure the reason is because they're tyrannical richardwads.