Why S-70 and not just plain Blackhawk? If you have just spent your last farthing buying, arguably, the world's best AH, why would you want to buy a very expensive support helicopter with AH pretensions? I quote from the company blurb:
"The major Battlehawk weapons feature is the 20mm GIAT THL 20 turreted gun. Past weapons integration on the Blackhawk using the External Stores/Weapons System (ESWS) have included Hellfire missiles, 2.75-inch Rockets, Stinger Missiles and various gun pods including 7.65 mm, 20mm and 30mm cannon. One current operational configuration has dual 30mm chain guns, dual 7.65mm machine guns and Hellfire missiles and rockets, more than doubling the firepower of existing attack helicopters."
I always thought SH were supposed to carry ordenance for other people to fire.
I also don't think that the concept of soldiers carrying soldiers to the front line, leaving the rear echelon load lifting to the RAF is a player. The full potential of AH requires the ability to operate from FARPs (Forward Arming and Refuelling Points) behind enemy lines. BLUH will never be able to support AH by itself. The US Army concept calls for a sqn of CH47 for every AH sqn. I think we could do it a lot better than that, but it is definitely a Chinook job.
Most infanteers that I have spoken to would also prefer to be delivered by the might Wokka. The lads have an understandable aversion to facing the enemy in small packages and like to fly towards the front line with at least 39 of their mates on board. The CH47 can carry at least 4 times as many troops as any likely BLUH contender but doesn't take up anything like 4 times as much room on the DZ which means that the planning staff can maximise the concentration of force on the first wave and bring in reinforcements and heavy USLs at the same time on subsequent waves.
Like it or not, the CH47 is almost always the choice of the front line customer. Light support helicopters are the choice of accountants and senior officer taxi-cab services.