Why is the arc for arty so ridiculously high up?

well like i said it's only at t3 that units ever had noticable min range.
t1, they didn't.

so translated to PA, that would give : only static arty has min range and t2 mobile arty can't shoot itself in the face

I was there, I remember it, but fixing pelters by giving them a crazy high trajectory was not the way to go. Changing damage / splash would have been a better option. So would a minimum range, which I actually like the best because then you completely eliminate the problem of long / medium range arty (holkins / pelter) being more effective than the laser towers at short range.

I also disagree, minimum range is not very micro intensive at all. It is virtually no more micro-intensive than checking max range when placing the unit. Just show 2 rang rings when placing the unit, one for max, and one for min. The extra amount of time for a person to process the minimum range ring in addition to the maximum would be negligible.

Not unless you brought your long range arty to the front lines for some inexplicable reason.

Or unless... the enemy moved towards you.

You don't want your artillery to sit there doing nothing.

Just a bit of a technical question here, marginally related; it seems as though artillery takes into account (and the trajectory affected by) the coriolis effect. Is this the case?

That's why you protect your arty and make sure the enemy doesn't sneak up on it. I'm all for less micro, but there is a certain amount which I think is acceptable, keeping track of what the enemy is doing is one of those things. If your opponent manages to get a bunch of short range units to your arty, you should have had a more mixed army so you could protect it.

Surely artillery should be for long ranged defence whilst laser towers are for units that get close?

There's mobile artillery as well.

But do we want those to be effective against armies? I feel that artillery should serve base orientated roles: either offensive for siege purposes or defensive to soften up advancing armies.

It really depends on the kind of arty that you are using, but that is what I was getting at. Look at my previous post with the picture. Long range arty should be using a lower trajectory that what we see in PA. PA uses a high arc which best fits mortar style arty which is the shortest range

Different trajectories for artillery are situational. If you have direct line of sight on your target, a low trajectory shot would be used (like a gun). If there is terrain blocking your shot, you can clear that terrain and still maintain range with a medium arc (like a howitzer) finally if there is an obstruction directly blocking your shot of an enemy that is on the exact opposite side of the obstruction you switch to a high arc low range shot (like a mortar).

Modern arty can have a very wide range for elevation so that it can fill multiple rolls. One of the cooler things that can be done now is MRSI (Multiple Round Simultaneous Impact) (http://en.wikipedia.org/wiki/Artillery#MRSI) where one gun can fire multiple rounds at different trajectories so that all the shells impact at the same (or about the same) time.

I imagine smaller planet sizes also has something to do with it. Pretty sure if the big pelter fired straight or close to it, The shot would clip through the ground on 200 size planets, with its radius.

The question then is if guns like that should have same radius, or radius should be dynamic based on planet size.

Well it wouldn't clip through the ground since.. Y'know, simulated projectiles- But it would hit the ground by accident! And explode.

yes that is very likely since if you remember, when the booster didn't pop in space but crashed back down (which I still want back, BTW) they would be affected.