The shields make no sense and should probably be armor instead. 20 strength is less than half a layer of armor, will be destroyed easily by just 3-5 missiles or weapon shots, and I shudder to think about how much tonnage you're dedicating to get such a small effect.
Deployment time 24 months makes not a lot of sense especially with only 11b km of range. I'd reduce it down to 12 months and bump up the range. If you run into a situation where you need ships on station for more than 12 months at a time you'll probably be better-served to tug a recreation station to that position, as the upfront expense will be made up for by designing more efficient combat ships.
4000 km/s is rather slow for an ion-era beam ship. I'd try to get at least 5000 km/s, at 4000 km/s you will struggle to close with enemy missile ships at the same tech level. Additionally, I do think 11b km range is rather low, it's not unmanageable but it will require you to always have a tanker pre-positioned or you will be waiting for a tanker to show up for a large part of your total time during an operation. I usually design my fleet warships to a range of 30b km but even 20b km is probably fine, this should often at least allow a fleet to reach its station and then engage in an operation while waiting for the tanker to show up and refuel them for the trip back home.
If you're not stressed about fuel conservation, an "optimal" propulsion design (maintaining a 3:1 ratio between engine and fuel mass) would be 2x size 48 ion engines with 1.50x EP modifier, which along with 1.4m L fuel will get you over 5000 km/s and 20b km range. If you want to be more fuel-efficient and keep the same "form factor" so to speak, with 2x size 60 engines a 1.10x EM modifier will get you to 5000 km/s. If you haven't got the EP modifier tech...well, it's 500 RP, so what's the holdup? But in that case, at 1.0x modifier you can get 5000 km/s with 3x size 43 engines.
Enough about engines. Looks like you've got two spinal lasers, just be aware that come 1.13 it will no longer be possible to mount multiple of these as it is considered a bug that you can presently. Your spinal laser could use the Recharge 3 capacitor instead of 4 to save a few minerals, as you'll get ROF 15 either way. The overall laser loadout looks a bit light but since you are also mounting Gauss turrets I think it looks about right all together. Do note that due to an obtuse collision of statistics and salvo mechanics, smaller Gauss weapons are more optimal for PD with sizes 1 HS and smaller being the best - it looks like you're using a larger size, which won't be crippling just a bit sub-optimal.
Your PD BFC would benefit from a longer range, presently you will only have about 78% accuracy in PD fire as final fire takes place at 10,000 km range. I would probably try to get 96,000 km range on the PD control as this puts you close to 90% accuracy (good enough, any more would mean diminishing returns) with only a 1.5x size multiplier at worst.
Your reactor is a good bit more than you need, you have 8x lasers at Recharge 4 so only need 32 power and you're producing 42. I;d either cut that down, or push up to 3x R16 so you have one reactor for redundancy in case of battle damage. However, if you convert the spinal lasers to only use Recharge 3 then your power need is only 30 so you should use 2x or 3x R15 reactors.
Note that you should make sure if this ship doesn't have passive sensors, you have a ship which does that can accompany it. A 3,000-ton sensor corvette with size 12 EM and thermal sensors will work well although you'd have to design a new engine for it.
