About flagship, I'd keep raid, bomber, flagship as part of the starting set, with possibly one version of riot. And that's baiscally it.
About the turrets, yes, I'm aiming more for "damage-oriented" types than others. That means that scout for example would be excluded, as would tractor and possibly the gravity turrets.
I wasn't able to find where, but I remember having the same kind of discussion with old community members (maybe even Chris). I proposed to lock away most starships and they explained to me why it wouldn't be wise. It's a basic toolbox that any player always have access to, no matter what RNG is throwing in the game. You can't remove basic tools from the game. Some can be more or less removed from the basic pool (the damage-only, for instance), but not the ones with special abilities. The same is true for turrets: tachyon, tractor, gravity, mines, etc, are basic tools for the fundamental towerdefense component of the game. Some damage-only
may be moved away in a shuffled list of random goodies to add in the game, but not all. I would be like moving the scout drone in the bonus fleetships pool because it's not part of the triangle: it can't, it's a needed tool.
However, it would be a good idea to have a pool of turrets from which RNG would pick some to add in each game (what it currently does with the fleetships). But that pool mustn't be made with basic tools striped from the "always available" pool. However, making that pool with many new turrets would be interesting. Let's just take the list of ship mechanism we don't find in turrets, shall we? Imagine engine damage turrets, reclamation turrets, vampire turrets, swallowing turrets, Neinzul (drone spawning) turrets, armored turrets, etc. That can make a nice pool of unlockable turrets that would not always be available in each game. But, believe me, don't lock away basic tools such as tractors, tachyon and gravity.
With starships, the call is even easier: the problem is that the pool of random locked starships is very small (6, counting the protector) and mixed with the fleetships, so there is few chances to get a starship design in an ARS or a design backup. So, same strategy: instead of locking basic tools, add more in the locked pool. And there is where it's easy: if all fleetships with cap <10 are made starships (they would be "high cap" starships), that would add a dozen new units into the locked starships pool. Also, if fleetships and starships designs are no more mixed together, it would be more common to have one random starship in the base mix. (We need to come up with a good idea for that; maybe something like, in the lobby, each starting position offers one fleetship, one starship and one turret from the unlockable pool.)
I can see a nice symmetry, easy for new players to understand. Three categories of units (for the Humans, at least): fleetships, starships, turrets. For each, you have a basic toolset that never changes and one more, different in each game. MkII and MkIII are paid with Knowledge, MkIV requires MkIII and the capture/hack of the advanced stuff of this unit type, and MkV requires capture/hack of a specific Core Fab. that grants a single unit MkV no matter MkI-IV.
It must be like a nice table, in the newcomers' heads: three columns for three unit types, one row per mark with the same mechanism: MkII-III Knowledge, MkIV Advanced, MkV Core. No exception, clean design.
