No. Listen to what I’m saying, not what you think I’m saying.
A design choice can be bad when designed with the philosophy I’m describing in mind. An overpowered rule that makes people think their current army is unplayable IS BAD, because it fails against the design goal of ‘people can play with their miniatures and have a fun and roughly balanced experience’. Obviously, examples like the one you give are bad.
But that’s an extreme example you invented for exaggeration. In the real world, there are rules that, while not the best choice for the type of game YOU want, are the best choice for the type of game GW is designing, which is much more casual than you think. Again, wanting a less casual game is fine, but 40k will never be a good game from that metric.
What is a ‘good game’? What metric should that be judged on? There isn’t a single metric that can be used: everyone’s needs are different. There will be some commonality, like wanting to not have the boomstick you describe above. But you can’t judge a game as good or bad without considering what its design goals are.