Some of those heavy troops are because the game decided to rudely vomit dozens of indy vampires on my nice tidy border. As opposed, I guess, to my untidy moving border with Shinuyama. But city guards are great for holding forts, yes. They're also resource cheap, which can be an incentive to pick heavier troops over them to spend gold better elsewhere - also the only real reason to buy falchioneers over elite warriors given a choice.
Longdead horsemen are a very efficient summon, patroller, raider et cetera. I have them because they are versatile, cheap and readily available. The opportunity cost at this stage in the game is low.
Regarding assessment of nations:
Vanarus has more focused summons to compliment it's national rainbows, and can make demons and thunderspam. It has simple tools on top of it's rainbow tools, excellent research and can do very well with high S or N on its' god. It's a fairly powerful nation, which should scale well with finesse, but almost always goes without some of its' summons. It is super thirsty for gold, especially if you use the forest wizards, but can use and find most gems, and develop large summoned armies overnight as a result.
Marignon will set you on fire, then shoot you. Later they will use extensive astral magic. Their national angels are hard to kill and remedy their otherwise lackluster path diversity, but ever air and earth spell marignon gets to cast needs to count. They are regarded as the worst luck nation in the game on count of their small range of paths - they flatly will never use nature, water and in most cases death, but with good mages who can lead 50 men each, they can overcome poor diversity by great volume of magic.
Asphodel surprised me. Usually freespawn and D magic beats crossbows and MR-Negates weapons and spells put the hurt on the Ulmish, but they just folded. I'd have loved their cap, and my high MR lizards could likely have taken it, but geography failed me.
Oceania are Pangaea with water instead of earth, an underwater start instead of the best berserker if not best unit in the game, no maenads, and far less unrest. Still strong, not rushable, but likely a downgrade. They have a favourite school of research to stick with, which helps.
Ulm has most of the best elemental spells in the game, a solid troopline, and poor ability to use or withstand sorcery. Everyone knows their strengths and weaknesses, most can guess their scales, and they make an excellent introduction to the power of cross-path magic.
Arco will mind hunt everyone they end up fighting. Don't leave the house without astral magicians. Elephants without any means of flight will become useless sooner rather than later. They do crosspaths about as well as ulm, but the healers and mind hunters are their most unique power and they will wield them gleefully. They might be the only nation that wants to fight vanarus in the lategame. Arco will have an awake pretender, also to go with the healers.
Shinuyama scales with mountains. Their best raiders come from the mountains even without forts, and they need temples and labs in those mountains to spam shaman. The bakemono sorcerer looks great, but is ancient, limiting his power in battle, and slow to recruit mages for nearly 400 gold are somewhat painful. Uba's are pretty amazing, though. WN is a good crosspath, WD is a good crosspath, d2 is great, w2 is w4 if it has to be. That's scratching the iceberg, and unless I win this war against them I'll not crack it open.
C'tis is enchantment five's greatest hits, with some extras. Your magicians are good, you have an assassin who makes skeletons in battle, your basic troops have MR 12, your dominion makes you rich and others poor/hagridden, but knowing exactly what to research before your first war is likely your single biggest strength here.