If Half Life 3 does get produced, it should have more guns but at a controlled amount. This was what the fans agreed on after some individuals were suggesting for Half Life 3 to be an arsenal warehouse like BioShock and such.
Of course, this is not to say that the guns in Half Life 2 are sufficed. Yes, the weapons fit well with the game’s plot but they could use an extra variety or two. The new weapons for Half Life 3 should also be introduced in the same manner like all the other weapons before this.
Also, Valve should not disregard the purpose of weapons like how hand guns and shotguns are for zombies, SMG for groups, pulse rifle for bigger groups, rockets for the monsters and the rest for a more artistic way in killing.
For most of the fans, they are content as long as the crossbow and gravity gun is not removed from the inventory list. Both are fan-favourite weapon and they are the ones that made the Half Life Series an interesting game.