I think this thing deserves its own thread. 

From the conversation so far, I we have

• Generic turret, if to be used for SPAAG, some stuff can be added, like
  • (better?) Radar
  • (more?) Laser target designators
  • different FCS (does this make sense?)
• 40mm CTA gun
• solid missile capacity (2 bays in my thinking)
  (my thinking here is that
  - The SPAAG would not suffer if it had 8 MANPADS
  - More missiles would be useful in HIC)
• Flexible missile bays to accommodate either x ATGM or y >x MANPADS or other light missile.

IMO this should be an RWS, but with an option for the commander to stick their head out is so desired.

Now, what I am wondering is the question of radar for instance. Would it make sense for a regular IFV to have radar, not least for ground surveillance?

Modular does seem to be the flavour of the time, or at least the ability to swap and change to fit the desired capability and/or budget.

To that end you'd probably want to start with a core to which things can be added if needed rather than building everything in and leaving parts unused

A missile launcher that can support a range of missiles would be good, provided that doing so doesn't increase the cost of each launcher substantially. A SAM would likely need higher elevation than an ATGW, and the guidance systems may vary depending on the specific missile system. Having more missiles is a double edged sword since missiles are rather expensive, fragile and large. Being able to add more missiles to a dedicated missile vehicle would seem to be useful, so having the ability to mount multiple launchers without having to mount multiple launchers on all vehicles.

Radar is a potential problem in that it emits and can therefore give away your position to enemy electronic warfare systems at somewhat greater distance that you can detect targets. The British high velocity missile system included a scanning infra-red system in place of radar for that reason. That said, some of the active defence systems use radar which has to be fairly effective in order to pick up incoming missiles in time to do something about them and to know that they have to do something about them.

Yeah, I have been wondering about ADS. That would be pretty short range radar though?

As regards modularity, I like that idea. Being able add missile launch modules at will would possibly be immensely useful, especially if it gave an option for adding more than usually anticipated. It fundamentally would give field commanders space for mad ideas.

Radar range is a pretty complex subject, but what little I understand says that the range depends on the target, so is an incoming missile a bigger target than a drone?

One thing that strikes me with modular connections is that a missile launcher could be swapped with a directed energy system or other alternative weapon or reconnaissance/targetting system.

well, targeting-wise my thinking is that the AA version might eg carry 8 StarStreak and could have 2 target designators, enabling it to launch at 2 targets at nearly the same time.

Also occurs to me that for AA both the rotational speed and rotational acceleration might want to be higher than the IFV turret?