[Tyrant]

F9 and W9 are the blesses that are problematic. Attack and defence skills are very difficult to buff with spells- there are no easy ways at all. On top of that there are very few mass summons that have high attack. So, to take the classic example of W9 Vans, once you add 4 defense to their already formidable defensive skills and Glamor you end up with a troop type that cannot be countered with regular troops, and then they get the excellent ability of Quickness on top of that. Quickness is a multiplier- the more deadly the unit, the better Quickness is. Same deal to a lesser extent with F9, hitting more often is good, but it better if you also do more damage. Again, it's a multiplier.
And the real kicker is that they work so well together.

So as i see it, it's the pairing of the excellent, universally useful and near unique skill bonuses with two other excellent 9 bless powers that causes the alleged problem.

One way to fix it would be to leave the L9 powers be and replace the L4 effects with something less useful. The other way would be to replace Quickness with another power.

Having said all this, I'm not fully convinced the problem is really all that bad. I've played quite a few games and i have yet to actually encounter the much discussed 9W/9F bless on the field of battle.