Wikipedia

you don't get any/sufficient recognition for your contributions. The closest they have to upvotes and reputation is the incredibly obscure "thank" feature which is only visible to the receiver itself: en.wikipedia.org/wiki/Help:Notifications/Thanks
deletionism is a tremendous problem on Wikipedia, for two main causes:
- tutorial-like subjectivity
- notability
The stuff you wrote can be deleted anytime by some random admin/opposing editor, examples at: Section "Deletionism on Wikipedia".
This also possibly leads to Edit wars in the case of sub-page content (full page deletion is more clearly arbitrated).
Scope too limited, and politics defined. Everything has to sound encyclopedic and be notable enough. This basically excludes completely good tutorials.
Insane impossible to use markup language-base talk pages instead of issue trackers?! Ridiculous!!! That change alone could make Wikipedia so much more amazing. Wikipedia could become a Stack Exchange killer by doing that alone + some basic reputation system. Some work on that is being done at: www.mediawiki.org/wiki/Extension:DiscussionTools, already in Beta as of 2022.
Edit wars