From the trailer, we know that AoE4 is going to be in the same era as AoE2 and will have a different gameplay from AoE3. I think that this is a reboot of AoE2.
Probably Microsoft was thinking about AoE4 but was not willing to take the risk, so it pushed for the DEs first since they will be less resource intensive. The success of the DEs determined if AoE4 would be made.
AoE2 was a huge success but now in 2021, the Advanced Genie Engine is almost 23 years old. So they will be recreating AoE2 from the complete scratch fixing all civ identities and focusing more on covering the world in 16 - 20 civs rather than covering Europe in 25 civs and rest of the world in 12 civs. Honestly it will be hard to select 20 civs from such a large pool.
So I have some suggestions for the game:
- Cover the entire world while selecting the civs. 1 from North america, 1 from South America, 1 from New Zealand/Australia, 2 from India (maybe Rajpoots and Tamils), 2 from South East Asia, 2 from East Asia (China and Japan sure), 2 from Central Asia (Mongols confirmed, +1 other), 1 from Africa, 3 from Middle-East to North Africa and 5 from Europe (British confirmed), 1 from North Asia.
Yeah, as of AoE2 we love Europe with the Teutons, Franks, Lithuanians, Britons, Celts, Vikings etc. But a decision has to be made.
Being strict with time period and multiplayer will help. A fixed time period of defining the middle ages say 500 AD to 1350 AD can help in filtering out the civiliations. It will be better if civiliations were selected on their popularity to encourage players from different parts of the world rather than selecting good campaigns on strong leaders and forming a civilization around them. Different campaigns can have the same civilization, not affecting History too much. The tale of Fredrick Barbarossa could have been implemented as Franks too and historically justified.
Delay AoE4 unless it is playable. We will enjoy AoE2 DE until then.
Better unit classification. I see this is being implemented in AoE2 as well using the Genie Editor. But it can be incorporated at the release making things much easier. For context, like how foot archers, cavalry archers and hand cannons have all separate classes. Some bonuses in AoE2 do not make any sense, but have been made to affect the entire class of units or only a particular unit. Example - Suuplies affects the Sword line exclusively but should also affect similar units like Teutonic Knights and Berserks. Pavise used to grant +1/+1 armor to all foot archers. Unluckily this included skirmishers.
Adding the concept of Civilizations and sub-civilizations (idea from a thread). This can help when expanding the game to 40 civilizations like AoE2. All sub-civilizations of a civilization have a common geographical location, architecture, military tech tree uptil castle age, 1 common unique unit. The 2nd unique unit be unlocked in imperial age when the sub-civilizations would differ militarily as well.