It's very individual. It's finding the right balance between training technique and 'brute' strength. Fact of the matter is, MMA is much more like ballet than it is a 'strength' sport. It's primarily technique based, though a lot of technique can be tossed to the wind in the presence of EXTREME brute power but the best is to have a balance of both.
Why is Fedor's technique so good? Cause that's all he spends time working on.
Think long term.
If you only have say... 4 hours of which to train per day, lets say you spend 1 of that lifting, another 1 doing conditioning, and 3 working on technique.
Over a year 300+ hrs of lifting...
Or it could be 300+ hrs spent sparring, hitting pads, etc.
that 300hrs is a HUGE deficit...
that said...depends how you're training. I'm sure you've all seen the video of fedor swinging the sledgehammer, using kettlebells, etc... Fedor technically is still "weight training" it's just strongman style kinda.
Imo, previously when he was lifting (if you've seen him with the pics of "mass gainer 1000" he was probably lifting a lot more like a bodybuilder.
If he was focused more on relative strength which would involve bodyweight progressions before using weighted movements then maybe his view pt would be different. Obviously no offense to fedor but a 375lb bench isn't that much for a guy who was probably around 230-240 at the time, that's just 1.5x bodyweight...and that's a pretty shitty squat...especially a 1rm.
Anyway that's all conjecture because we know what he HAS done in the sport using his method and it makes sense. While I think weights can be used in a smart way to enhance athletic prowess and perhaps make up for areas that you're weaker in... obviously the #1 thing you need to be worried about is your technique.
Drill, drill, and then drill...