There is no doubt there is something good for gamers coming. We all have our opinions and wishlists. I am that Half Life 2 fan who play it once every year (also Halo MCC) . Here is my wishlist/prediction (with a generous dose of hopium and copium and all other iums )
I think they are making not 1 but 2 Half life games. Half life 3 for steam PC and Half Life Alyx 2 for Frame. both game takes place in same timeline but from different POV with some overlapping missions. it could be really amazing if you think about it. I know it is similar to many other games (like my personal favourite Nier Automata) but experiencing it in flat screen and VR could just be another level.
But more sane side of me thinks that so much effort in 2 single player game wont be worth it for valve so there are probably 2 multiplayer games(L4D3 for VR and TF3 for PC with skins and lootbox) and 1 Half life game will be available at launch.