Key points, with some additional info from other sources:

• Game is published by Akella and developed by F3 - a fairly new team, but composed of veterans from other developers (several from Nival).
• The game is built on a modified Silent Storm engine with updated graphics, improved physics, FX, and damage model.
• There will be no more militia training and sector defense, because players supposedly don't like micro-management. The focus will be shifted towards combat and away from economics. As for strategy, the focus will be on missions, rather than on conquering territory.
• The player can command only one squad of up to 6 (maybe 8) mercs.
• Inventory handling will be simplified, particularly with respect to ammo. [In SS they used a backpack model with no item stacking.]
• The player's avatar will be generated without the personality quiz.
• Combat mechanics, RPG system, merc hiring, weapon repair, healing, etc. are all transplanted from JA2 with little or no change...
• ...except for the turn system: instead of having alternating turns for different teams, the order will be determined by character initiative. This system is said to be more conductive for multiplayer [although, AFAIK, multiplayer is not planned for this game].
• There will be night and day, plus weather effects, which can be seen on the strategic map.
• The team can move around the global world on foot or on wheels. However, on the tactical map vehicles are stationary. They can be used to store stuff, and some can shoot as well.
• Key locations are designed, but "random encounters" will be randomized. [I am not sure just how much freedom of movement the player will have on the global map.]
• There will be 40 mercs (12 of them new), plus 40 NPCs.
• Plot: the president-for-life in a banana republic is fighting local insurgency, while a neighboring country opened a second front in a bid to annex some territory. Meanwhile, an international corporation is conducting some sinister experiments in the country.
• You can play for one of 4 factions, each with its unique bonuses. In addition, there will be a 5th, non-playable faction - something having to do with a sci-fi subplot (which, as in JA2, can be turned on or off in the options).
• Income will come mainly from your employer (whoever it may be). You can also sell stuff to merchants... if you can find them.
• Merc relations will be modeled after JA2. Opposing factions will routinely hire mercs from AIM (remember Mike?...)
• There will be 20 key objectives given by your employer, plus, as in JA2, optional side quests obtained from NPCs. Missions are non-linear: more like JA2 missions (e.g. taking control of SAMs or liberating Tixa) than like in Silent Storm.
• Weapons will be reworked, with many JA2 weapons dropped and some new ones added - both well-known and experimental. Weapon specs will be adjusted to emphasize differences between different models. More different ammo types will be added. There will be more different armour, with heavier armour impeding movement. No more mortars. There will be anti-materiel rifles (12.7mm) and stationary heavy MGs.
• Initial load-out will be more generous than in JA2.
• No more cats. No bugs either.
• No information on release date.