One thing to notice is that for what we know now, the main turret is quite ineffective against ground troops. While Vanguard could one shot infantry in a 10m splash, you now need a direct hit. That will mean that main turret + Flak cannon will leave you awfully vulnerable to agile infantry who are gonna stick a decimator up your ass
This is something I was thinking about myself, but considering everything I am not overly worried.
Also, I personally sort of preferred using Sparrow MAX as NC over a Skyguard when I needed AA. Then again it was easymode-AA, but I was more mobile without relying on others.