I don't know of a timeline sticky, but just the detailed posts you probably already found by searching terms like "history" and "year" "changes."
I also don't know of a risky year (or a less risky year). I had a certain preferred year range in mind when I was shopping, but it wasn't about risk so much as it was about my preferences in the combination of feature changes that have taken place over the years. For me, the range of around late 90's to mid-2000's provided the best combination of various things for me, but they are mostly just preferences not "better" vs. "worse."
I did nonetheless consider a 2009 22 that was built by Fluid Marine (even though I had my preferences I was still open to just about any year). It had some nice touches, such as the V-berth had three hatches already installed and the belowdecks area was finished (white) and had two mini-bulkheads separating the three sections. In the end I really didn't want a high top (and it was a high top), so I went "back" to my earlier year range preference. I ended up finding a 2002 that filled the bill.
So to me there are three main things:
1) The particular combination of features/changes you will find on any given year and how it fits your preferences.
2) The way the boat is outfitted - engines, electronics, canvas, etc. and how that matches up with what you like.
3) And the big one: Condition. To me, in any boat over around a year old, it's condition and care that really make the difference. It's easy to find a 20-year-old boat that looks better than a 3-year-old one (of any make) if the former has been stored indoors and babied vs. say, sitting neglected in a hot, sunny saltwater slip (just to use two somewhat opposite examples).
The one additional thing (but this kind of goes along with #3) is that most all fiberglass boats make extensive use of coring/sandwich construction, and most all production boat builders do not seal it with more than caulking. So core condition is something to watch for and check out prior to buying (any year).
Sunbeam