I don't understand the purpose of AoE4

First of all, I think the game is really, really good. But it is also really, really similar to AoE2, more than I thought it would be.
And that's the problem. These two games are in competition to each other now, and this will be unhealthy for both communities.

Imo they should have given AoE4 either a different setting (for example modern world, which would also be more in line with the initial plans of the AoE franchise) or make it more different from AoE2. Now it is basically AoE2 3D and I think this will accomplish not much except to tear the community apart.