I haven't played much of it, but isn't Destiny of an Emperor a standard turn-based RPG?
It is, but it has character-recruiting mechanics and character management. There are over 100 enemy generals you can recruit over the course of your career, although none level up so only the core story party you acquire is viable the whole game.
Also, the damage system is (extremely loosely) based on the number of soldiers your characters command, so your "HP" also determines attack damage, and the tactician system actually requires you to choose whether it's more useful to have a high-INT character in your active party, or to use him to maximize your MP total-equivalent. You can do both, but it's more difficult to manage since it sucks to have your strategist die mid-battle.
//total DoaE nerd who learned too much writing an editing tool for it
Regarding Suikoden, since the war mechanics of the first game were so simple, I don't think it 'needs' an inspiration. Water Margin itself has narrative very similar to what happens in battle ('X, Y, Z led their knife-and-shield warriors into the fray...').
Fun facts, since we're talking about Suikoden anyway... the first game may be a fantasy game, but its narrative structure. characters, and many of its events are direct parallels to Water Margin (poisoned tea, the luring of Lepant, Fire Spears). The second game is actually inspired by Romance of the Three Kingdoms. Initially that's less obvious, but if you start drawing out the various locations on a map it's very clear.
All of this would likely be more readily apparent to a Japanese audience more familiar with the novels, which are fantastic by the way. More readable than some science fiction.