In reply to Chris Craggs:
> 1) if it would be E8 to on-sight then it should be H8 - that is the point of the system,
Well ... yes and no.
On average the idea is to have the two grades comparable, you're right. So if you approach an H7 with a view to trying to onsight it you should expect - on average - to encounter climbing at about E7. However some routes are just fundamentally tricky to onsight, relatively speaking, so your H7 may turn out to be E8 because the holds or moves are so blind or because the gear is so obscure or fiddly. Conversely your H7 may be pretty obvious (while still hard and/or dangerous), so it may be 'relatively' easy to onsight, thereby meriting E6.
It sounds like Franco has grasped this subtlety and has adjusted the H grade from the expected E grade due to the unobvious and sequency nature of the climbing.
I also expect that no more than three people in the universe will grasp this and because of that the H grade will never catch on unless we just use it like a simple E->H letter replacement as you presumed would be the case.