Let me ask you something: are you expecting a Fed to stay out in the sticks for its entire fuel lifetime at a time (i.e. six months or a year) without coming back for a resupply of, say, cargo? Or even just for shore leave? Y'know, places where it's likely they can get a fuel top-off as well? A year's supply of antimatter is excessive if the ship is nearly always within 1 month or less of a refuelling site. Having the ability to sprint clear across our territory twice is great, but how often is that going to be useful? If the ship would be required to run across the whole Federation to deal with a crisis, then clearly A) it's not that time-sensitive, or B) there's almost certainly another ship closer - and if there isn't, that's a failure of Command to properly allocate responders, not a failure of the ship itself.