I rather like the idea of Enclaves becoming mini-Hives or carrier, but I do have a minor objection. If you are going to remove the ability to build MIV units from the new mobile space dock could you at least give me at MSD MKII or something similar so I can still get my MKIV fleetships? And perhaps something similar for starships? I know that most people won't use it, but I actually do get the Enclave MKIV. I know that it will still cost at least 15k worth of K to get, but given that I have 4 exo sources and rather high levels of AIP in my games, I never get to keep those neat little capturables unless they are behind my choke. (I am really looking forward to a hack that lets me keep/move/ect Fabs) Three of my exos show up at the same time every time and one of them is FS. And while the obscene K costs make such things of little to no value for the majority, if you are cheating for K (like me) or playing FS (like me and several others) you CAN make use of their gimmick.
I like the Enclave MKIVs, they allow me to build larger (and more powerful) fleets of normal ships so I can have a strike force of that isn't just either FS units or starships. This gives me a mobile defense force for dealing with things that can bypass my choke. I have learned the hard way that no choke is perfect and with things like minor factions, Counter Attack posts, and certain AIs, I need to have some kind of mobile force that can cover my backside. The Enclave MKIV gives me a big enough, strong enough, fleetship force to manage these things so I don't have to constantly pull my main force back whenever something happens/is going to happen. Plus they can rebuild the units I am losing while the fight is going on, so even against a Counter Attack from The Core I can put up a fight without having to pull the main fleet back.
tl,dr- Please leave something that can produce MKIV without an advanced factory (and maybe add something similar for starships) even if it costs 15000 K. It may be gimmicky. It may be useless is many, if not most, cases. But there is at least one player who gives them some love, and I am willing to bet that I am not the only one.