The notable exceptions are when you need the actions but aren't sure you'll hit $4 again soon (Ambassador war and probably some other things), Shanty Town (which is usually not for the Village effect but the draw, this is effectively an economy/cycling card in the early game), and Hamlet (which you often open with just because you hit 5/2, but sometimes you get it so you can use the plus buy to get more Hamlets).
Those are precisely the kind of "subtleties" a rule like "never open with a village" doesn't tell you.
You know these things from a wealth of experience, but an intermediate person still blindly following the rule does not, and once he gets beyond the village-idiot stage, he really should start replacing rules of thumb with proper understanding.
These types of heuristics aren't for noobs only, I use them on a regular basis to evaluate boards and make decisions. They help make complex scenarios more manageable, and focus your thoughts on the important strategic considerations.
Yeah, but for noobs these things are and should be fixed rules, as that's the fastest way to improve and you can't learn when to deviate from rules without first having some solid experience with sticking to them. However, once they have that experience they should stop seeing them as fixed and start actively going against them, or they will never graduate to the level where you know--not "know" like a fact you looked up, but truly know on a visceral level--that they are merely useful heuristics.
They effectively compile the statistical results of a large number of games played by a large number of people.
And as such they provide you a quick ascend to the plateau of mediocrity
I've always found that making the rule explicit actually helps me see the exceptional cases.
This is a good point.
You might say "Cursers are important" gets you the same effect, and that's probably true, but "Never skip Cursers" also tells you which side to generally err on: buy those Cursers.
And that last thing is exactly what I see as bad advise. Well, it's great if all you care about is maximizing your win % in your current game, as you almost certainly want to in a tournament match, but outside of those you'd ideally focus not on winning this particular game but on becoming a better player. In that case, when faced with two options that look at all close, one of which is familiar to you and something you know how to execute well, while the other is something novel you have rarely tried before, you should always pick the last one. You want to try ignoring the curser if you think you might be able to get away with it, just like you want to go for the engine even if it looks a little wacky and you suspect BM-X to be slightly better. Not because these things will bring you the most victories right away (they won't), but because in the long run doing this will make you really really good in deciding under exactly what conditions to deviate from the obvious path. This is something you can't learn from an article or from a forum post or from "the statistical results of a large number of games played by a large number of people". You can only learn this by getting out there, by experimenting for yourself, by deliberately deviating from the standard rules a little (or a lot!) more than looks reasonable to your uncalibrated eye. You learn far more from things that don't work out but potentially might have than from reinforcing yet again your age-old habits.
I'm saying this not because I think you personally don't understand this, but because I think there are quite a number of people who read your post and come away from it thinking "yeah, better stick to the rules", even though that really is the opposite of what they should be doing, as by far the largest hole in the games of good but not great players that I encounter on Goko is not that they haven't learned the rules, but that they've learned them too well