New sections are created when current sections become flooded with topics that don't belong in them. Also, everyone actually has to care that these topics don't fit in the section.
As far as I can tell we have neither of these conditions.
There's also the fact that this website is called Halflife2.net
There are plenty of other websites that cater for your love affair with Half-Life, the game. However, I wouldn't be entirely against a forum called "Half-Life Lore" where you can discuss the story elements of Half-Life that are built upon in Half-Life 2 and its Episodes. Oh, wait, it already exists. It's called Single Player Mythology
Ep:1 and 2 should be put separately as EP:1 and HL2 forum should be meged
First, larger amount of people are going to use EP:2 forum at the time EP:2 is released. That does not apply on EP:1 forum since EP:1 was already out for months. Thread-population will decline constantly and it will not rise again. Therefore EP:2 is going to own the population so EP:2 forum should stand alone. For EP:2 and Half-life 2, fewer and fewer people use them so they can be merged together,
Second, when EP:2 is out, it takes a period of time until the majority has owned the game. In this period of time, people who played EP:1 or Half-Life2 will not wish to see any spoiler of EP:2. If EP:2 and EP:1 is put together, people will be forced to read the spoilers (title of a thread can be a spoiler). So it is necessary to put EP:1 and 2 separately.
Third, EP2 and Half-Life2 should be merged. There will be a better management is there are less things have to be manage. If there are too many sub-forums in a forum, the site will just become dumb. When there is less forum, the information is condensed. This can provide us the greatest convenience.