Fantastic post. Very Happy to see that in this forum are still not competitive players representing the majority of possible players. Competitive players are definitely overrepresented in this forum.
At the beginning all patches were really only for non-competitive players mostly trivial balance changes. Matches for non-competitive players are not decided by small balance differences. I am not saying there is no need for balancing. But the focus should not be so extreme on it.
The AI does not behave intelligently in many situations. The bigger problem I see is that the AI is not lively enough. It should be more like in AOE3 or even better Stronghold. That you really play against someone and not against a faceless AI.
Although I like history very much, the campaigns are too much documentation and too little immersion. The AOE2 campaigns would be a good example here.
There are too few different plants and animals on the maps. There should be at least the same as in AOE3.
There needs to be more game modes and settings for custom games. Fortunately there was a super moderator who made the mod advanced game mod. But even here I expect more possibilities from the developers.
Also, the prize money for the e-sport tournaments is way too expensive and not interesting for non-competitive players. The money would be better invested in mod developers.
These are just a few examples. The list could go on for a long time.
Please developers if you want AOE4 to be successful and have a long life: Expand the mod tools possibilities as much as possible and focus more on content for casual players. The referenced video is very good and can give many clues what can contribute to a successful RTS and what to avoid.