@koboldcurrychef You may even enjoy playing those types of games with Your regular opponents - as in, the group provides the enjoyment.

Besides, the "short, tournament scenario" in VQ and HIS - in my experience - is not that short, because of all that diplomacy-ing and talking around the table :)

Have fun on Sunday!

@grayson @FredKiesche My wife has said this: "You don't need all those games". She is right - I don't. Some time ago, two years or so, I have decided to concentrate myself on a single particular period in history. GMT Games does not publish that many games on that period - and the games that are in their preorder system can exist there for several years. For one title, I think, I have waited for around four years now. Maybe I am outside of the mainstream names and games?

So, even with the most recent update - the company does not provide me with any difficult choices - their preferred designers simply do not design the games about my selected period. I am "safe", I have no need to use a bunker myself.

GMT Games nowadays have so many projects in the making that they can seemingly carry on with what they are doing now - relying on recognized names that attract the customers.

Popular designers craft new titles and before the first game in the new series is even published, the second one in those series is being officially announced within the preorder system.

@Alphawolf One can start with small scenarios. One can start with period that is of the most interest to Your son. In my time with wargames, my own interest was usually the best guidance even with more demanding wargame systems.

My ranking, in terms of accessibility, for the games that You have listed:
1) Hoplite / Cataphract
2) GB of Alexander
3) SPQR
4) Julius Caesar

In each game, there are smaller scenarios and those may be better for the newcomer to GBoH. However, Hoplite in this list is an odd one, as it has a different Activation system.

Hoplite and Cataphract, however, has scenarios that may end up pretty quickly, sometimes even in one or two turns, especially if both players will go for frontal attacks.

SPQR has maybe the biggest "footprint", by which I mean it is very easy to sit down to a really big scenario for some famous battle... but it also has several small scenarios that give the taste of the volume without demanding much time.

I am wary of "Roman" games for the beginners, because their Roman command system rewards playing well - and this means that it is easier to fumble around if one is new. ... On the other hand, I have been using C3i scenarios like Elis and Lamia to do precisely that - introduce the newcomers to Roman command system in smaller battles.

I hope that this helps. I sincerely hope that Your son will find the experience with the game enjoyable - ultimately, that is the most important thing, I think.