It is evident that the Return of Rome expansion was a letdown for the community but I personally predicted this. The goal of the expansion was to try and replace DE while simultaneously making it more like AoE2 (big mistake in my opinion) and make it appeal to the notable Vietnam community by adding a Vietnam civ.
The core issue though is that because it is a hybrid of both 1 and 2 it does not appeal to neither diehard fans of AoE 1 or fans of AoE 2. By making it like AoE 2 you are alienating the fanbase you are trying to appeal to. The Vietnam community will not abandon their main game for this.
Instead DE should be refocused on and made with certain updates would be able to appeal to the large playerbase in the East that are still playing 1998 RoR. Making Classical mode playable online (maybe even it’s own ranked ladder), adding hotkeys for upgrades/age ups, adding the D3 gamemode, fixing the ai in free for all, possibly add the new Vietnam civ and maybe include some more exclusive brand new civs or a new unit. Most notably give players the option to play with the balance of the original games.
By doing things like this it will make DE completely outshine Return of Rome and appeal to the players you are trying to obtain. AoE 1 is an iconic game and very much deserves to be treated better than being reduced to a dlc that makes it play like a different game.