i think years ago when the capacity of cells wasn't what they are now, and you struggled to last, the performance difference between LiPo and NiMH would've been way more apparent. Nowadays, if you've not got enough speed, you can just slat a faster motor in the car, yet not even come close to using the full capacity of cells.
There are limits to what power you can use in an off road car without making it too just too difficult to drive (grip limits etc), so i really can't see a performance related benefit of running LiPo in off road.
I ran LiPo in my X6 at the weekend, with a Novak 7.5L, and it was more than enough power. I was slowly adding weight to the car to get it to the same weight levels as it was with NiMH, so power really isn't a factor
The benefits of LiPo in terms of usage totally outclasses NiMH though. I have one pack for 2wd, one pack for 4wd, and just recharge the same pack after a race. No matter how long i run for, both cars' electrics came off cold! Overall, the cost of 2 packs of LiPo TrakPower 3200's cost me 90 quid (ish), cheaper than the numerous packs of cells i would've eventually bought for the new season.
As for fitting LiPo in the cars. I agree with some of the comments about attracting newbies into the sport, and them maybe having to mod the car to make it LiPo friendly. However, there are quite a few cars that still require some form of dremeling to get them race ready!
to be honest, i'd be gutted if we couldn't run LiPo next year, racing has become so much easier since i've tried LiPo
