Mark IV split:
I don't really see much point to it, at least for me. When I build enclaves, they generally just end up as Spacedocks that I can more easily relocate, that also can provide a minor military force to whatever system they're in. I generally don't use drones, and I don't usually use enclaves for supporting fleets away from home, so aside from increasing the energy costs of having the full set of enclave starships it doesn't really do anything with how I play the game.
Cost reduction:
1000 knowledge less is nice but doesn't really matter on an 18000 knowledge investment - even at 17000 knowledge it's 6 worlds for just mobile production facilities. Shifting the final cost from 14000 knowledge to 12000 knowledge is more useful, since that's a change from 5 worlds of knowledge to four worlds. I think that the problem is more that if you want to open up the full enclave line and get something worthwhile for the last 12000 knowledge (14000 currently), you're essentially asking players to increase the number of planets they take by about 50% to 100% in a non-superweapon game, assuming that normal levels of conquest involve taking 6 to 12 worlds on an 80-planet map. That, or knowledge-hack enough planets to get enough knowledge.
I think that most of the problem people have with Enclave IVs is that, in 'normal' games, it very nearly looks like you can either unlock the ships you'd be able to build out of the Enclave IV, or you can unlock the Enclave IVs. If the expected number of worlds taken in a normal game is 6 to 12 planets, this isn't likely to change unless knowledge costs of either Mk III fleetships and turrets or the Enclaves themselves is significantly reduced (note that I haven't played since 6.016, so if the knowledge costs of any of these has gone down since then this might not be particularly applicable). Let's assume that you'd normally unlock 2-4 Mk III fleetships in a game. That's 17000-34000 knowledge, or 2-7 planets and the homeworld (assuming you unlocked both Mk II and Mk III), and most likely you'll have other unlocks that you'd get in a 'normal' game which bring you to your 6-12 total occupied planets. Since most likely you only take about as many planets as you need for knowledge for your 'normal' game (enough to cover fleet unlocks, economy upgrades, and extra defenses), we probably have no more than 3000 spare knowledge by the time we have our 6 to 12 worlds. If Mark III fleetships cost 4000 knowledge apiece rather than the 6000 current, then we're looking at having an extra 4000-8000 knowledge in a 'normal' game, which makes the Enclave IV much more reachable at its current cost, since if we've got this 'extra' 4000-8000 knowledge we're only looking at 3 or 4 extra planets to take (or raid) rather than 6 extra planets (possibly less, since we might have that 'spare' 3000-ish knowledge), or at skimping a little on the defensive/economy unlocks.
So basically I feel that a large part of the Enclave IV's problems would be solved by making Fleetship IIIs cost less knowledge. Reducing the turret unlock costs would also help for people who like drones, but I don't really care one way or the other about drones. Spreading the knowledge cost of the Enclave line around a little more would also help, as saving up that last 14000 is a lot less tempting when I could instead take more forcefields or better harvesters or more turrets or more ships before I ever save up enough knowledge. It's kind of like looking at real-world purchasing habits - I might not be willing to spend $50-$100 dollars on a game all at once, but a $40 base game followed with two $20 expansions and the handful of $5-$10 mini-expansions/DLCs spread out over a year or two? Same with knowledge unlocks - I'd sooner take several unlocks for 2000 to 6000 knowledge as I gain the knowledge than save for one unlock at 14000.
Cloaking/Brave toggle:
Sure, why not. I usually leave them at home anyways, but having cloaking and a 'brave' toggle can't hurt.
Automatic Drone Production:
As long as there's a way to turn it off without shutting off the entire enclave, I'm fine with it. I can think of situations where I might not want drones spawning but I do want to make use of the Enclave as mobile production facilities (mostly, when I'm hugging the energy brownout line to spare my economy from the costs of more than the absolute minimum number of matter converters I can run the fleet on, or if there's something I don't want to wake up on the planet and I don't want to bother with catching the drones when they spawn).
