I think what Andrew is maybe trying to say is that in designing a 'Jack of all trades' you are actually reducing the overall feasibility of the design. Although, I realize that you are roleplaying 'dumb designers'
What size in tons is that thermal sensor? Can you create a smaller one? And then with the saved space try to fit more missile launchers?
To be honest, I don't think that 2 missiles every 55secs is going to be able to damage any attacking ship of substance. I do not have Aurora on this machine so can't show you a design of mine, but I have a 6000 ton Destroyer that could probably catch and destroy your survey ship.
If I recall correctly, it has:
1 CIWS (so has a good chance of knocking down your 2 missile salvo)
6 armour
6 shields
4 size 8 launchers with missiles of WH4 that do ~20000km/s
ion engines for total speed of 3000km/s
Your 2 CIWS might actually save you from this design as I think I only have the one fire control. But, I operate these destroyers in groups of 3 or 6 and so would any NPR or Precursor that you run into.
I have never felt that need for an armed geo and grav survey ship, but I might try and design one when I get home and see how it compares to yours.