So here is a philosophical question : Is diversification of fleets better than specialization? As in the navy ONLY consists of fast beam ships or battleships with beam OR have a fleet with missile corvettes and carriers and beam ships with geosurveying capibility and stuff like that?
Diverse fleet of specialized ships is ideal, to cover each other's weakness. Missile boats can reach next to forever but run out of ammo, beam ships are pretty 'short' raged but unlimited ammo. Then there're specialization within each field of PD, offense, defense. Such as gauss being splendid point defense at very short range and mesons being viable for mixed PD and anti-ship purpose and AMM being able to fire at missiles far beyond beam range.
It's still better to have generalized fleet function split along military, civilian and survey line during early part of game since there're not enough resource nor developed techs for real specialization. Once you can develop specialist ships, it's pretty much time to optimize it for a specific role or against specific enemies. Though this wouldn't take in account for focusing on one weapon or defense field over other, it's up to the designer to make it flow together.
Also, I'd laugh if you turned your survey ship into gunship surveyors
Not that it's not viable in hostile territory, but it's rather bad compromise concept. Survey ships are better expendible, IMO, or at least designed to not cost too much. Put a thermal sensor on it, so they can at least tell you what cooked it, though!