Are such tag wikis considered good?
The specific one you listed as an example is not really good, no.
Should they be removed or edited?
If you mean remove the tag, then you need to raise a burninate-request question on the relevant site, suggesting which tag is not useful, too generic, dupe or could be a synonym etc.
If you mean remove the description then they should be edited if they are no good or could be improved. If that means re-writing the entire thing as the current text is completely gobbledegook, then sure wipe it clean and start again.
Essentially, the target is "improvement", and that leaving all, some, or none of the current text depends on the specific tag and current text.
A lot of tag wikis contain vague buzzwords and read like
I agree, however this is what community moderating is there for, so we can as a community improve things and suggest edits to tag wikis and such like.
Then if the general consensus is an edit suggestion improves the tag wiki/excerpt, then it will be approved.
I'm not sure (exactly) what problem you are reporting, other than there are some poor tag wikis/excerpts which could be improved.
Yes there are some terrible tag wikis and excerpts, so just edit them :)
There are also thousands of good tag wiki and excerpts, so I don't think there is a large enough issue here to be concerned or to have to do anything specific or new.
Just edit them as and when you see poor ones, or when any improvement can be made.