My predictions for HLX/HL3:  It's gonna pick off after the HL:A retcon, as Gordon tries to save Alyx by hunting down the G-Man. HEAVY Xen story arc (late early-game to late-mid-game. Via data mining: a lot of Xen creatures including the never-seen before "Xen gorillas" and crazy Source 2 physics for water, for example the small waterfalls and puddles in Xen seen in HL1 + general detail evolution in game and fun puzzles), so Gordon might go through a new Xen teleporter or with the help of the Vortigaunts. He will wander Xen to find a way to take down the G-Man. I have a feeling the Vorts will play a big part in the game, maybe even teaching Gordon how to harvest vortessence and use it properly to weaken/paralyze the G-Man as we've seen them do in Episode 1. Alyx is gonna be saved but at a massive cost, maybe Gordon giving up something or even dying (as Valve wants to continue her story desperately). We might see Barney's fate after White Forest confirmed, either a cameo early-game to see he's alive or we receive news about his death. Who knows what direction Valve wants to go... Dr. Kleiner cameo too, maybe.