I answered ‘longer’, but I’d like to add the caveat that summaries are very useful for ‘best of both worlds’. Any ‘longer’ part could be summarized at the top of the page (even if just to say something like, “Exceptions are covered below.”)
I guess a main theme I want to get across is that, IMO, more info is always better, but it’s also the organization of that info that makes it more-usable or less-usable. Summaries are a good example of this. Having an extra ‘reference section’ to expand on things is another good example. You can make it easy for casual or cursory reading, but also provide additional information ‘off to the side’ so to speak.
I take a lot of inspiration for this approach from the concept of a Wiki. Of course everyone is familiar with Wikipedia, but not all wikis need to be ‘encyclopedic’. Indeed the first wikis ever were more for just collecting and sharing ‘good ideas’.
One of the most significant features of wikis are the usage of hyperlinks to refer to concepts/ideas by name, without having to explain the concept/idea every time; if someone wanted to know what you meant by some technical term, they would just click on it to quickly read that page about that specific term, then jump back to the original discussion where it was being used, and they’d be up-to-speed in no time.
You get to have concise explanations backed up by extensive documentation/reference (and discussion, in the original wikis, but that doesn’t apply so much in the BunPro grammar term situation*) at the same time. Like I keep saying, ‘best of both worlds’. 
[* Although maybe it does apply, since I also agree with several previous suggestions to have some way for users/community to crowd-source things like examples and references and whatnot, and in particular to provide feedback/ratings/whatever to help good suggestions bubble to the top of the heap.]
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