@Ubiq:
Water 7 and Ohara are two very different propositions as far as a Buster Call goes. Water 7 is very important to the World Government as it seems to be one of, if not the, primary shipyards for Navy vessels. It's a major trade center that is vital to its neighbors and possibly that entire section of the Grand Line. It's massive and almost certainly capable of defending itself as they regularly deal with pirates.
That's true, they are very different. Yet, consider this. While the World Government and Water 7 seem to both have benefited one another, think of the reasons why this came to be in the first place. Iceburg wanted to get in the WG's good graces in order to scale down the investigation on the blueprints, and the WG wanted the blueprints for themselves. So much so that they used the CP9 agents to infiltrate Water 7. Now that the blueprints are gone, Iceburg's and the WG's primary reasons for being contracted to each other are now dissolved. We all know Iceburg is no fan of the WG, but his concern for Water 7's well-being most likely far exceeds that. I can't help thinking that the government may take some action agaisnt them, but I doubt it'd be a Buster Call. Right now, I'm sure that it has been reported that Iceburg is dead, since the CP9 thought so. Which would have benefited the WG if the Mugiwara pirates were sucessfully framed. So, that brings another problem into the mix. Another point could be wether or not Paulie and co. keep quiet about Lucci, Kaku, Blueno and Kalipha's role to the rest of the city. They may not want to work with them anymore, despite the advantages due to their respect and admiration of Iceburg. Though, I'm sure things will go on the way you described, I just thought I throw some points from the side of them not getting back on good terms.
@Ubiq:
Ohara was an out-of-the-way island specializing in a science that most people in the Odaverse are probably suspicious of anyway. It was also consistent with the World Government's policies to destroy the place. It was small and defenseless, but more importantly, I doubt that the international community made all that big a fuss over it.
Attacking Water 7 would almost certainly be a public relations disaster for the World Government at a time when that's the last thing that they need.
This is what mainly throws a wrench in the theory that Iceburg and WG won't get back on good terms. If they do take action, I think it would be to remove Iceburg from power or try to find a way to hush the situation.
@Ubiq:
Oda might throw a Buster Call task force at Water 7, but the one we saw in Robin's flashback made perfect sense from a military standpoint. Water 7 wouldn't.
I doubt the Water 7 citizens will even see those ships. I agree, it wouldn't make sense from a military standpoint.
I hope I made a bit of sense. :unsure: