Even the looks can change as we see with the recent makeovers. All of what you said is why I feel like it's BS every time Disco says buying a ship should be a commitment (whenever players are complaining about having their ability to trade ships around constricted). Yeah, that might be true when the game is live. Right now though, even flyable ships are largely a question mark.
Operational cost versus profitability is a whole concern on its own (and I think some cap-ship owners are going to be upset by that if CIG holds true to what they said in the Polaris Q&A). But from a real-world money perspective, let's say you have $400 in the game and that's your limit. Do you buy a $350 large ship and a $50 starter ship, knowing that the $350 ship will be extremely costly and difficult to acquire in-game? You could have had a bunch of cool smaller ships for that price, but those are also much easier to earn in-game because of the way prices increase on larger ships.
Yep, even looks have changed, but mostly they have changed to look more like the concept image then to something else. As for the 400 to spend on in-game ships that is the billion dollar question and I do not know what the answer is and I get the impression that not even CR and his directors know. While they might have a general direction they would like to go in they have also shown a willingness to listen to the community and adapt the game play to match the communities desires. We could easily see that the 350 dollar ship by itself is incapable of turning a profit until it is utilized in a large fleet. Or ships like the Carrack while possible to hit a huge payday could spend days and weeks looking for that needle all the while gobbling up a sizeable initial investment.
It could also be that the Idris and Polaris are capable of taking on high pay missions but before you are trusted you have to grind out lower missions to build up enough rep and while it would be possible to do it in those ships you would need a sizable initial bank.
My personal stance is, do not forsake the midships and only have a starter ship and a large capital as you'll most likely find yourself grinding out credits in your starter for a long time while your capital sits in the hanger. Even large transport ships like the Hull C/D could take a sizeable initial investment to purchase enough cargo so that the profit off the sale covers expenses of fuel, crew, and protection. Most games start you out at the bottom and as you learn the game and progress up the tree you gain the capital to make the jump to larger ships. Buy being able to buy ships we can artificially make those leaps without having the game experience and/or capital to support it. Which can leave you in a bad spot especially if you upgrade your starter ship to a larger ship and then have nothing to use.
Make sure you have a good starting ship and then feel free to fill in your fleet with whatever tickles your fancy.
The Aurora and Mustang will always be good ships as they are intended to be starter ships and so the gameplay will be there for them.
The Freelancer, Reliant and Cutlass also are great starting ships as they allow you to do a lot of different tasks while being easily flown solo. If you have a group of friends that always play together then the Constellation would be a good starting ship.
If fighting is your jam then the Hornet, Gladius, Avenger, Buccaneer Hurricane, Defender, Hawk, Vanguard and Sabre would be great starting ships and in fact, I do not see these ships ever not being useful even after a year or more.
Racing if you are skilled will always be profitable from the start but it would be best to get the kills in alpha before it starts to cost as racing while not winning is going to be costly.
If mining is more your style then the Prospector is a no brainer. While it could be possible to jump straight into an Orion and get going especially with enough help from the corp it's still going to have a difficult time and a degree of luck without having enough credits to support setup costs. In fact, I would say if we as a corp focused on mining to start with after finding a mid-grade astro belt then this would put to work a lot from flying explorer craft to find rich nodes, Hull D/E to haul the ore back and fighters for protection while the Orions do their thing.
The Apollo, Mercury, SRV, Vaucan, and Crucible could have missions available from beta onward (could still require enough rep to get the missions) or they could rely more on player generated content in which case they will be hard to utilize until the game starts to mature. They can be helpful in a mining operation but their need and usefulness would be greatly limited. The SRV might be needed to move cargo from the Orion to the transport ships.
Ships like the Hercules, Starfarer, Caterpillar, Hull C/D/E will either need you to utilize one of the starting ships to generate enough starting capital or have you start with a sizeable bank account given you'll need to buy the cargo, before hauling and selling it at a profit. The other usage is as mentioned earlier with hooking up with the corp mining and hauling the ore to market.
Dropships like the Valkyrie, Prowler, Vanguard Hoplite, and Retaliator Base would require large scale combat operations and those tend to always be money sink and typically not attempted until the group has enough capital to start pushing into new territory to find new gear and wealth. The Redeemer might end up being a dropship/gunship in which case it would fit here but its really an unknown ship at the moment.
Bombers (Eclipse, Retaliator Bomber, Gladiator) like dropships are best utilized in fleet operations along with the Capital ships (Hammerhead, Polaris, Idris, Kraken, Javelin), ground vehicles (Cyclone, Nova).
The Alien ships like the Scythe, Khartu-Al, Glavie, Blade, and San'tok.yai are being built out to be very costly to operate with high prices on replacement parts.
The Merchantman might fall into the same group as the haulers but it has been rumored to be able to have internal stores in which case it could be possible to play the long game with low overhead on buying and selling ship modules to players. Of course like the haulers having more starting capital will only help.
The 890 Jump, Genesis Starliner, Endeavor and Constellation Phoenix do not have enough information about their intended gameplay elements to even speculate on.