I wouldn't be overly concerned with the payload.
I've run Engineers pass, and I'd do it again in a Gladiator. The switchbacks might take an extra move to navigate, but not a big deal.
Add weight in the bed and it'll likely be a tank in the snow.
Just saw that the Rubicon is only rated for 4500lb trailer towing, and only 1200 payload with the 6 speed manual.
Guess it's a good thing I'm holding out for the diesel.
Both 4500 towing and 1200 payload are likely to be fine for me, but why limit myself?
JT Rubicon
3.0 w/auto (or lose patience and go 3.6 w/MT)
Hardtop Unpainted (& unpainted flares)
Cold Weather
Proximity locks
Black cloth interior
Solid black wheels if offered (& it looks like they will)