People tend to whine about certain mechanics/items when they see 1 or 2 members doing well with it. It's completely natural and god help us if the item balancing team / developers listen to those desperate cries.
It's amazingly easy to disable a mauler, but seems easier to whine about it on forums.

I can leave a couple of tips here for those having an hard time:
1 - NEVER try to stab a mauler. The block stun will mock at you and you're dead.
2 - AVOID at all costs doing obvious overheads, for the same reason stated above.
3 - KICK ability is priceless versus a rushing overhead mauler if you don't have the time to hit him first.
4 - BLOCK (or CHAMBER if you're comfortable with this mechanic) those side swings, with concise hold blocks, the side swing animation of the maul induces in error, since it's slow, and connects weirdly, resulting most of the times in a knockdown.
5 - RUN from a mauler when he's surrounded by YOUR team mates. This is a TH nest situation and the way overheads connect on the mauler are deadly. If he knows how to time and turn properly while spamming overheads, you don't want to be near.
6 - USE polestagger ability if possible, either yours, or a team mate.
7 - SHIELDERS hide your shield on the back if 1 on 1 a mauler. The shield won't help at all, and only make you slower.
Another good observation is that the deadliest maulers, are the ones in medium (loomed if possible) gear, who don't have to rely on glancing hits from enemies while spamming away. A good combo of speed + PS is priceless.
Hope this helps in anyway,
Cheers