It depends on which nation you are playing. A smaller nation or even OPM will use the defensive idea group as the first military group; more attrition for enemies and better forts help you to live through wars against bigger opponents.
On the general issue I believe Offensive is nearly unconditionally superior. The difference between 0 and 100 AT is less than 2.5 mean pips in each skill (tests). +1 yearly AT increases the equilibrium level by 20 at default decay rate, and by 33 with Innovative. Assuming AT is linear (it must be on average on the interval between 0 and 100 AT), this translates to less than +0.5 pips per skill (+0.83 with Innovative), which is less than the full +1 from Offensive (excluding Siege, but I'm choosing to focus on field battles here since this is where generals are most decisive). While capping out general skill at 6 (and thus wasting the extra pip) is not taken into account by this analysis on the Offensive side, neither is capping out AT on the Defensive side, which is far more likely especially with Innovative.
As for the idea groups in general, I play SP exclusively, so...
I think the more salient point in the analysis is that you get most of the useful stuff out of Defensive in the first two ideas whereas the ideas you are comparing in Offensive take up the whole group. Even going so far as the Siege leader bonus, that's the 3rd idea or so?
Here is an example of offensive only on the left, and offensize + quantity on the right, full maintenance, year 1693:
Quantity never had that much impact on my country... Are you sure you dont have units being repaired?
Which, incidentally, is really annoying. One of the great things about EU3's sliders were that they were always a trade-off. You could be offensive, or defensive, but not both. The more defensive you became, the less offensive, and vice versa. I dislike that in EU4 that there's no real such thing as specialization - taking a particular idea group never blocks you off from any other idea group.
Which, incidentally, is really annoying. One of the great things about EU3's sliders were that they were always a trade-off. You could be offensive, or defensive, but not both. The more defensive you became, the less offensive, and vice versa. I dislike that in EU4 that there's no real such thing as specialization - taking a particular idea group never blocks you off from any other idea group.
Looks like noone here prefer nobility, but out of all mil ideas I take it first. Cause early game cavalry is substantial power, and nobility allow to have nice bunch of cheap! cavalry togather with increased manpower, extra diplo(Very good bonus for early game) not mentioning discount on mil tech later on. Defencive is good idea I must agree, but if you have high traditions and prestige + morale boosting advisor you can have like the same morale advantage ot the other hand other ideas from that branch are not that good.
Since quantity mostly boost cost and manpower its good if you are poor, but if you can affort fighting with mercenaries and/or already developed administrative then quality rocks.
My personal rating of mil ideas is following:
1. Nobility
2. Quntity(if poor)/ Quality (If I'm rich)
3. Offencive or Defencive same value for me
Aristocracy and quantity ideas could sure use some buffs. Same for the administration and probably even the espionage ideas.
However, whenever playing MP I'd always take Defensive first, because Offensive only gets really good at the end of the tree whereas Defensive's best ideas are at the start of its tree
Wait he's complaining that the weakest portion of defensive is the rason it's overpowered? what?
Yes defensive is OP, but god no it has nothing to do with the attrition reduction.