All good points. Lets not forget about those who have access to War Elephants.
To a certain degree, we should forget about them in general while remembering them in the few, very few, situations where they make sense. War Elephants are a one trick pony (well, elephant

) that, at an outrageous cost, are only truly useful to those who cannot recruit heavy infantry and do not have cavalry either (or have cavalry and low tech and isn't willing to spend ideas on improving his cavalry).
Code:
A/D Cav Militia Hinf WElph
Cav 1.0 1.5 0.7 0.5
Militia 0.5 1.0 0.75 0.25
HInf 1.2 1.25 1.0 1.0
WElph 0.75 2.0 1.0 1.0
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Archers 0.75 2.0 1.25 1.0
Harchers 0.75 2.0 1.25 0.5
Attackers - rows, defenders - columns.
As a slow front line unit (and hence useless in a fast army), the only thing interesting from a damage perspective is how much damage it deals versus other front line units and how much it takes from the front line and the rear shooting line.
With the lack of ideas or decisions improving the war elephants - but easily available to cavalry and heavy infantry - and the additional significant tech bonuses over the first 20 levels or so (of which war elephants benefit the least), elephants come off in practice as being significantly worse off in the long run than their already unimpressive stats would indicate.
As can be seen, for anybody who
does have access to heavy infantry, using war elephants in the front line instead of heavy infantry is a remarkably bad idea - unless he expects to be fighting mainly militia armies.
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Don't get me wrong - I
like war elephants and find them a reasonable substitute early in a game if I have no heavy infantry recruitment possibilities, cannot acquire it via a simple trading route, and, at the same time, have a very strong economy.... it is just that, for the most part, the conditions needed to make recruiting them worthwhile seldom show up for the nations that can recruit elephants in the first place.