So let's talk about Artillery.
We plan on having a very different approach to artillery than Relic's, one that incorporates the doctrine and methods of each nation to give more flavour and options. It's a bit more realistic, though still streamlined and sped up since we don't think most players want to wait three to fifteen minutes for the shells to arrive.
The biggest change is that most artillery is kept off the map, leaving only infantry guns and medium mortars on the map with few exceptions. Off-map artillery batteries are controlled through an artillery observation team, which is either a small infantry team on foot or in a vehicle. The observers can radio for artillery support on a designated area, as well as choose the type of bombardment and any other options available to that nation. They can designate targets beyond their normal sight range, but only up to a certain distance since they still need to be able to see the impacts, so they have to accompany your troops and can be killed if you're not careful.
Off-map Artillery has three different response tiers that are chosen when you purchase it: Under Command, In Support, and In Reserve. Under Command means that the battery directly subordinated to your Battlegroup and will respond immediately to your requests if they are able. In Support means that the battery has been assigned to you as well as a few other units in the nearby area, so it might be busy doing a fire mission for someone else and you'll have to wait. In Reserve means that the battery is being held back by your superiors, so you won't often get the chance to use it. Obviously In Support and In Reserve give a cost discount when purchasing artillery, though all three tiers are not always available depending upon your nation.
Red Army artillery is unique in that it has a fourth option: Pre-planned Fire. The Soviet Union had a shortage of radios to equip observers, and usually anyone trained well enough to be an observer was kept at the artillery headquarters rather than squandered on dangerous assignments. This means that they instead relied on highly-detailed firing plans that were decided upon before the battle started. Pre-planned Fire allows you to designate artillery targets anywhere on the map, but you have to wait for a few minutes at least before the guns begin firing, making it useless for reacting to a rapidly changing situation. However the Pre-planned Fire allows you to field not just a battery, but an entire battalion (three batteries, up to 12 guns in total) and the cost discount is quite high to make all those guns affordable, giving you a viable way to smash a defensive line before you move in with your ground forces. If you go for a response tier other than Pre-planned Fire, your observer team will not be as effective and you'll be limited to a single battery of four guns.
Speaking of national differences, German doctrine was pretty traditional and called for precision fire with short salvos. They wanted to conserve ammunition and make every shot count, but the calculations needed to achieve that accuracy slowed down their response times. Fairly effective at eliminating specific targets that aren't moving around, but not effective at hammering an area for a sustained time nor for hitting moving targets.
American doctrine was an evolution of the French artillery doctrine that pioneered some concepts of centralizing the artillery in an area under one flexible headquarters. The calculations were simplified to speed up the response, but without sacrifing too much accuracy. Also since all requests went through a centralized system (A fire direction center, located off the map), there was a chance that other batteries in the area could help out if they were available too. Being tied into a Fire Direction Center is an extra upgrade purchased ahead of time and is only available if you take the In Support response tier.
British doctrine emphasized highly-trained observation officers that had a lot of leeway and authority. They also simplified their processes in other ways, so British artillery responds faster than any other nation. Observation teams have the authority to request fire from more than just the battery they came from - similar to what the fire direction center for the US provides - but using special codes like Mike Target and Victor Target that can be used a few times per game. Also British batteries were the largest of any participating nation - eight guns at full strength - giving you a great deal of firepower if you can afford it.
Rocket Artillery also functions differently than conventional guns and howitzers. Obviously they saturate a large area in a very short time with their inaccurate rockets. However the smoke trails generated by their rockets reveal their general location to enemy artillery, so after one or two bombardments they will have to pack up and relocate to avoid counter-battery fire. When this happens you'll be notified, along with an ETA on when the battery is ready to fire again. Also reload times are much higher with rocket artillery, so you'll have to wait longer between bombardments.