Yep thats a pretty fun list man. You've got a bit of target saturation so they have to worry about focusing down the death-star (which they probably will) or the backfield gun-line, ignoring one or the other could potentially be fatal for them, depending on the army.
Decurion is very powerful, don't get me wrong, and its good to play a few games with it to understand how resilient your army can be. Even taking a single harvest or cult by themselves w/ decurion can be very effective. It depends on your meta and what your up against. Against the big guys you generally should take it most of the time as the ability it gives you to not die is very helpful.
I play against Nid's, ork's, AdMech, and
IG so I don't go up against the big boys as much. It gives me a lot of flexibility in what I want to bring. I also have to bear in mind the power level of my stuff and not bring the cheese. For instance I would never take the stalker/
HD combo again unless up against stupid amounts of
AV.
Basically when building lists you need to think of what your army is up against and how you are going to counter it. E.G I bring alot more tesla and particle beamers when up against blobguard/nids as they run a lot of troops. Against admech scopes on the blades are invaluable. Like I said before you also need threat saturation. Bringing stuff like Ghost Arks/spyders etc can take enough fire off the actual important stuff until it gets what it needs to get done, done.
Few little other things. If you are not going to take any other heavy support slots split your
HD's into 3 squads, meaning they can focus different things/ not waste as many shots per turn.
Again, while you do have mid range AP2 and a warscythe, potentially drop a stalker and add some praetorians in. Even better is to take the praetorians and the stalker in their formation, giving the praets pretty awesome buffs during the game. You will still be able to give the
HD's their buff, but also give some close range AP2 shooting/
HoW charging/AP2
CC options, on jump infantry, meaning alot more mobility. If you need the points you can drop your warrior count down. Warriors not having relentless out of decurion means they cant double tap and then charge so your missing out on the ability to tarpit non-dedicated
CC squads, which can be done ok by large warrior blobs.
Another feature of the
CAD is running two min squads of immortals, thereby severely dropping your points investment down to fulfil the
CAD requirements, enabling you to run more fun stuff in other slots. Bear in mind there are good things in every slot so if they get filled up quickly, remember to look at allying in some formations, as it gives good buffs to good units and takes them out of fast attack or elite for example, freeing up space for things in the
CAD (I.E running a canoptek harvest takes wraiths out of
FA slot, enabling you to run an other squad of 3 tomb blades with vanes and looms and tesla that can be backline objective campers until you need them to turbo boost and grab linebreaker/objectives in the opponents backline. Not necessary, just an example).
So yea, hope this helps mate. Just play around and have fun. Necrons are a very fun and very strong army if built right, but they can be depressing to play against. Bear that in mind when playing against friends. If playing in tournies etc then go as cheesy as possible!
Enjoy
12,000 