I honestly don’t know why the sentiment is that hordes are too hard for Cataclysm. This isn’t a “lol scrubs get gud” post, trust me.
They’re challenging, obviously, and require not only a strong character and good equipment to survive but also a lot of game knowledge. In short, they are perfect as is because they’re challenging enough for the player to be considerably wary of taking them on whilst not being unbeatable, still offering the usual Cataclysm fair of being able to dispose of them in a hundred different ways, and actually rewarding the player for taking them on or creating them in the first place - if you play with Static Spawn then a horde has to come from somewhere, and when they’re dead there won’t be any zeds in that somewhere.
As for actually taking them on, I go for the most versatile approach. I start by setting up a killzone to funnel the zeds towards me. Then I start picking off the dangerous squishies - shockers, spitters, boomers and bloaters - with a sniper rifle. As the horde approaches I juggle in between thinning them out with sniper fire - prioritising one-hit kills, softening up brutes and hulks with grenades then finishing them off with shotguns or revolvers, and using melee for regular zeds. If things ever get too hairy then I’ll start lobbing molotovs, grenades, pipe bombs and using flamethrowers. A motorbike acts as a bug out if all else fails. I can elaborate on what you generally need to do if you want.
This is not even considering traps; sound distractions such as noise emitters; smoke grenades, stun grenades, flashbangs etc. for general debuffing.
My only issue is when the hordes seem to appear out of nowhere for no good reason. As in those times you’re peacefully foraging in the woods only to return to your base overrun with hulks.