Top 5 reasons why XGM is brilliant:
Stability - For me, this is a big one, and no doubt to many others. What good is a mod that, while well researched and bursting with features, crashes every once in a while? Or requires memorizing certain game breaking bugs that pop up in specific situations?
It's certainly no fun in the long run to have to treat a game like The Soup Nazi, doing things in a particular way just so you don't suddenly get thrown out. Being able to confidently leave a campaign unsaved for a good number of turns, or to not have to check for any obscure "aftermarket" fixes to download unofficially, is a blessing - and XGM delivers.
User friendliness - One download, one install. Now that's more like it! As fantastic as some other mods are at what they do, it just tiring to have to sift through outdated download links, semi-hidden file packs that fix bugs, poorly written installation guides and dead links.
And not only is XGM a breeze to get and install, it's mod foldered and gives you a few important (not trivial and non pertinent) options to choose from. Again, very clear and simple, and an example for others to follow.
Doesn't fix what isn't broken - Ambition is good, but few people have the skill, time, and resources to truly and successfully break a game down and design it anew without hitches, imbalances and general amateurishness. Not to mention the right to edit the source code! As talented and dedicated that the RTW and Total War modding scene is, I personally have not found a mod that strays far from vanilla and still stays coherent and uniform.
Complicated tech trees, convoluted and CPU draining scripts, and an overdose of new designs ("feature creep", as it's called in the game developer world) may dazzle the player in the short term, but often turn out to conflict with the game structure that CA designed originally - and most importantly - from a standpoint of user functionality. The reason that XGM has endured and gained the considerable stamina it has in the RTW mod community, is because it respects the core of the game it's based on.
Expand the experience, don't transform it!
Historical accuracy, not historical obsession - In the eternal battle between real life history and game play considerations, it's easy to get lost. We all want a measure of historical plausibility in our Total War games, as after all, that's part of what made the series such a success over the years. However, some mod makers tend to take things much farther than that, and cram their creation full of hyper accurate units and unit types, factions, tech trees and traits. I disagree with this approach. The most effective way to create a dynamic and entertaining mod is to let balance and variety come first, and then fill in the history - not the other way around.
XGM, like other classic and timeless works, is built on this simple foundation that has proven itself over the course of many years. Even if a certain Hoplite unit didn't, say wield a spear overhand or underhand when fighting, or if an archer unit was from this or that region, it's irrelevant if it improves the game play and looks and feels plausible. If I can believe it as a representation of history, and it fits in with what you could imagine actually existed, then it readily trumps excessive historical adherence.
Just what's needed, and keep the good parts in. That's great design.
Continued support and development - Last but not least, is the huge benefit of consistent attention and updating from the author of the mod. Solid, bug free, and polished design takes time. Lots of time. Slowly but surely you get all the aforementioned parts in place, and achieve that elusive state of gaming greatness that induces a feeling of "home" in its players.
You know what I'm talking about. The feeling that there is a safe place out there, a place that can be trusted to instantly and reliably satisfy your cravings for conquest, glorious campaigning, devious scheming and mighty armies crushing the spirit of their vile enemies. A place that feels like visiting an old, dear friend that, while sharing many happy memories of the past, can still just a easily provide new ones every bit as joyful as the old.
XGM is that place.