Before anyone gets upset, this isn't intended to be a rant about cheesy weapons and the people that use them.
I hear about it all the time. Whether it is a discussion about how to fight against it or how to use it, someone inevitably says "they're just skill on a stick". Heck, I'm sure I've said it a few times.
Of course, it isn't just flails we hear this sort of sentiment about. Cheesemail, low profile spears, 12 oz swords, punch towers, speed bats, and all sorts of other gear gets labeled as cheesy or overpowered. This is especially true when talking to newer fighters.
Obviously, the game can't be so imbalanced (or well balanced) that everything is overpowered. There are advantages and disadvantages to most gear. So why do we keep hearing [random gear] is overpowered? It seems a portion is due to exposure to the fighting style, which depends largely on the area one fights in. If you haven't fought against a weapon or shield design before, you have no preset method to fight against it, so you have to resort to your typical responses and attacks.
But that isn't all that makes something "cheesy", it has to have some advantage that people find difficult to overcome. Lets look at the max length (40" in Belegarth) flail as an example. The advantage it gets is the ability to go around shields and blocks thanks to the hinge. It takes practice, but those advantages aren't difficult to overcome by changing how you block and move against the flail. It succeeds when people react the same as they would against a sword.
Still seems too strong? Well, it is 40" long, your sword? Probably not that long. Even most longswords come in around 36" in length. To be honest, if you were to use a max length sword, you'd probably have an advantage over the flail. With the general trend of making lighter, faster weapons, flails begin to be stronger relative to the field.
This same sort of meta gaming lends itself to promote the other types "cheese", and whatever counters it. Cheap and easy armor to counter lots of spears, punch towers to counter flails, etc. The point here is that everything has a way to counter it, including your setup. If you find yourself constantly losing to one weapon or style, maybe look at your own strategy and style before labeling them cheesy. Maybe you've been throwing rock when you really should be throwing scissor.