Are you serious man ?Ace had Roger's blood and was on the ship of the worlds strongest man...someone who could of possibly made him the next pirate king and the was strong enough to protect Roger's last remaining attachment to the world (until marineford)
while Luffy holding the blood of the most wanted man was just a random pirate who the GOV probably thought would of died trying to become something.
The way I see ace's bounty is like being the right formula in the right hands. It's like giving the right weapon to the right criminal as opposed to just having a weapon roaming around. Both pose a threat but one if in under the right conditions to cause even a greater threat.
That's just they way I see things though, your view may be completely different
-luffy's father is the most dangerous criminal in the one piece verse
-luffy's brother is the pirate king son
-luffy is associated with the withebeard pirates
-Luffy break in Impel Down
-Luffy is associated with shanks who's probaby now the strongest yonko for god sake
-cp9 arc nuff said
this is way more than ace,what are you talking about man ?