Either that, or the gunship thing you describe... In military hardware design and construction, "superior" tends to be better than "inferior" - so whatever fighters we see, we should be able to deduce that their intended targets are smaller, weaker and/or possessing less range and mobility!
Superiority doesn't exist in a vacuum. A long-range shuttlecraft could have superior range to any other small craft in the Federation, but that doesn't make it a practical fighter craft, even if you stick a phaser on its belly.
If you have a gunship, it would be just fast enough and maneuverable enough to get in close to another small craft and disable or destroy it with some well-placed phaser fire. It becomes even more effective in a ground support role, and is more justifiable in this case: maybe you're beaming an away team down into hostile territory and don't want to send a bigass shuttle that will draw attention to itself? Well, your gunships are small enough; beam two of them into a parking lot down the street and have them standby until needed.
That would also be consistent with the OP's pitch. A power cell that has to be replaced after 24 hours of use doesn't seem very practical for a large craft, but something the size of a gunship (smaller, actually, since it has no tail and no rotors) is a very local operator and it doesn't usually even need to go to warp except to chase down somebody and shoot off his nacelles.