My worries are about maneuverability, flexibility, and utility.
Beacon.
I'm assuming the ships will be persistent while the owning commander is offline. If they are not, then what use are their services? Fdev did choose to make them indestructible....
If others (up to 16 others) are allowed to visit the carrier, then they must be able to find it. This means it will be a POI in the navigational display. If the name is customizable (which it will be cause the cmdr name is custom), then there will be the temptation to use the carrier beacon as a billboard. For this reason, I'm ok with upkeep, so long as its only to the tune of 10mil/week OR 30 minutes of "gameplay." Yes that 30 minutes should include switching to the ship and location specialized for whatever gameplay this upkeep requires, and back. In eve, jumping capitals ran on isotopes which were just abundant mining products that just took time. The upkeep and jump fuel should just take time and its acquisition rate be LARGLY UNAFFECTED BY RNG.
We also need to know what the intended effect is when this nebulous upkeep elapses. Will the carrier just power down and only be findable by owner until resupplied or does it completely depopulate until the owner pays up and then it turns back up at the nearest inhabited system? Obviously, that would be terrible, which is why we need details.
My NPCs.
If the support ships are going to be little more then a combat patrol, then having an SLF crew be in them would be pretty cool. Otherwise, why even mention the support ships as a feature if they just buzz around. Even if they aren't flying around the ship, having the NPCs I've kept be the ATC or crew would be pretty neat. However, I must request that Fleet Carriers take a back seat to the over due feature of getting a escape system for the NPC. Ships are disposable, skilled pilots are not, even if they are not in the Elite club.
We live in an engineered world.
Making ships and modules purchasable at the carrier is of dubious utility, at-least for me. Activity specific ships are laid out ahead of time, modules purchased, set aside, and engineered to spec. If these "operations" specialization module's main purpose is to make ships and modules available in the carrier, then I'll be disappointed. I refer to 100.rub's initial point that these "operations" modules need to be customizable down to the component level. Make the external appearance a purely cosmetic choice if you have to.
Schroedinger's cargo.
What makes a mining station a mining station? A combat base of operations? It's the BGS, the economy type, and services available. Assuming for a moment, the carrier is dissociated from those things and does not have a market on board, how is it intended to support piracy, trading, S&R, or mining? My answer would be "by having storeable cargo for loot, commodities, recovered material, and ore." Fdev has not entertained the possibility of cargo persisting outside the player ship since the game's creation and unless I missed it, has not said they will allow the carrier to store cargo. This must be confirmed. There is also the issue of ownership and capacity. Will the carrier have a shared capacity or is it tracked per pilot and the max capability is 10000 tons per pilot with permission to dock?
Claustrophobic pads.
These pads are far too close together to be using the current docking system prefab for outfitting and "going below." Are we going to see a new animation set or is there no outfitting unless you have a op module with fewer pads so the internal bays fit?
"Personal Fleet" carrier.
Will we be able to summon ships to the carrier like we can between stations? Will we be able to store ships in the carrier? If I had one of these I would put all the ships and modules in it that I use on a regular basis and every time an event comes up that might require multiple ships, jump the whole thing there and unload the "trailer." My worry is the way the carrier is laid out and based on what has been said, I wonder if the carriers will even have shipyard functions. In which case, their use will be extremely limited outside of providing a forward operating base for the squadron.
As you can see, I'm very concerned that a fleet carrier will just be a player controlled mega ship with limited services and no new mechanics that could make it worth the expense of owning and moving it. However, if the ship had some unique capabilities such as storing cargo or parking near locations of activity and being a meaningful base to live out of, it could be worth the expense, especially if it was easy to mothball. The prospect is very tempting to fire up the painite machine to pay for it, but we need more information about the ship's technical limits from Fdev as soon as possible so we can give them meaningful advice. CARGO? JUMPFUEL? SHIPSTORAGE? OVERCROWDING? EXPENSE TARGETS? Right now we are just spit balling about what we want the ship to do without knowing what it is within the technical scope. Can it even jump without a server downtime? The sooner we hone this in, the less of a chance they become a meme, like powerplay or multicrew. If that means it goes back to engineering for 6 months to add a feature, SO BE IT!
Until the incident in the Witch Head Nebula, we didn't have a lot of game play that could really use a a battle wagon like the carrier so it needs to be worth while in the game we have and the content we will get in the future.
And for the record, also support the OP concerns.