You never know though. The thing is, who would have thought that Luffy would have an archaeologist in his crew, though? There's probably room for one more. He did say in the beginning that "10 crew members should be enough" which sounds like it doesnt include him. I'm actually hoping Ace and Boa Hancock will join him for the last 2. After Whitebeard dies(a presumption of mine) and Hancock betrays the government(another presumption), they will destroy Amazon Lily and she'll have no where else to go, also taking her title as a Shichibukai. As for Ace, since WB will probably die in the future, hence losing his goal. Who's the next best candidate to be the Pirate King? Why of course he'll help his little brother! Who better to have on your crew than a former commander of the Whitebeard Pirates and a former Shichibukai? All of Luffy's crew and acquaintances have huge ties one way or another. Since Luffy is destined for greatness, it's only right to have 2 more crew members of that stature. Why would I think WB dies? Well the guy is hooked up to Life Support for Pete's sake, and it's been hinted all over the place that a "New Era" will begin, and that "The time of Whitebeard is over".

i think you're right about whitebeard.. ithink that ace never joins luffy..maybe after WB dead, ace will become the leader of whitebeard pirates...with marco helps i think..

if white beard die marcoh will took over not ace

if the crew is stronger then the captain there will be trouble if they were to disagree with each other in the future

maybe you'r right...we dont know how the story will end yet..but i really hope that ace and luffy become a rival..it would be fun..fire vs gomu gomu..

yeah..ace never want to be part of strawhat crew.he admire wb to be next pirate king