Are there any decent alternatives to challenge ratings?
Alternatives to CR
What's your gripe with CR?
Monster level.
How do you mean, OP?
And there's always knuckling down and doing some math to work out the general capabilities of your party and comparing them to monsters to figure out what's suitable. Average attack rolls vs defences, average damage vs HP, the ability to inflict and resist various forms of debilitating effect.
Initially crunching the numbers can be a pain, and you need to update it every level/significant gain in power, but if you're not going to be using or trusting whatever abstract value a system gives you for the threat a monster presents, it's the only way to go about it.
Gosh, I guess that means playing 3e or 5e is pretty stupid.
4e monster levels but that requires balance.
No. Everything is situational, so trying to nail down a precise 'this monster is X levels of dangerous' is always going to be shaky.
Well... duh?
But 4e uses pretty much the same encounter design as if you had CR (pick encounter difficult, fill up with XP derived from level/CR of monsters)
Yeah, its called max damage estimates and average damage estimates. Why the fuck do you need anything else? I dont know. Max damage estimates are good to avoid party wipes, average damage estimates are good to control challenge.