The LC I don't think is bad value at all - it's more natural competitor is the 6 series, E class coupe, Maserati Gran Cabrio. In many ways it is the true successor to the Mk4 Supra as a truly large sporting coupe. The new supra is not a large car, and neither is an RCF. They are midsized cars.
I don't think £70k is a terrible starting point for such a car given it's remit to go head to head with 6 and new 8 series BMWs, Maserati coupes etc. It has the newer 10spd box the RCF doesn't have, a more striking design and probably more luxurious appointments. An RCF's competitor is a C63, M5, RS5 sort of car. This is the class above.
I'd love an RCF but I think if I had the money I would buy the LC. It looks terrific.