If I don't have any problem with them, why do you?
Phyrex' Very Short Guide to Maul Defence
Never thrust or overhead.
Spam left and right slashes while watching for Maul side slashes. Should you somehow fail your spam or perhaps do a thrust by mistake, kick-slash him.
As a solo-mauler, aggression and constant W-key spam is a must. Heavy armour and the slow, short weapon requires constant 'up in your face' combat tactics. An easy prey for back-peddling, spam and kick-slashing.
An experienced mauler will try a side slash and see if you block or not. If you do block it, you should, he might try doing it again, but this time do a holded side slash. This will stun your weapon and he'll try an overhead straight away, keep the kick-key ready or simply backpeddle away.
The mauler isn't that awesome at taking out turtles, it's far better at taking out support players. Flamberge, Pikes and all the 2-attack direction polearms, slow polearms, defensive/str-whore players and newbie/clueless players.(Who got none but themselves to blame.)
And of course, throughout this thread, the people who complain wield the weapons/fit into the categories mentioned above. Amusing. Would be like me complaining at archers shooting me in an open field. Guess what? They're my counter-class, the maul might just be yours.