If this game is to reflect the period in question with any accuracy then its diplomatic model is the key. It should not be possible for one nation to just go to war with another country willy-nilly. If a crisis arises, nations should have to try and negotiate a settlement, or conceivably even have a settlement negotiated and imposed upon them by the Great Powers. Only if negotiations fail should war even be a possibility.
The EU system will surely result in the sort of situations that Generalissimo has described, and that's just totally wrong for the time period. The HoI system of War Entry is closer, but will need to be refined considerably if the game is really going to have a Victorian era feel to it. Crisis meters for each and every country might be necessary, like the way EU tracks relations between every country.
To get back to this thread's topic: if Paradox implements a robust and restrictive enough diplomacy system like what I've been talking about, then a World War I style battle should be a distinct possibility, even starting from 1835. Under a system like this, Great Power war presumably wouldn't be possible unless tensions are high. Yet even early on, having allies will still be important because it will give you more clout in negotiating and cut-down on the number of nations that you have to worry about crises with. If war starts to loom on the horizon and it seems like you've picked the wrong allies, tough luck. Because severing your alliance at that point would destroy your all-important reputation.
