Remember that tactical warp is still at a
low warp speed; and that the scale isn't quite so vast (10,000km per hex). Also, many maps in the other game systems are either "fixed" (set to cover a certain number of map panels) or "location" (as in, you can't move a certain distance from a given point or terrain piece without being considered to have disengaged).
While Earth fits within a single hex, gas giants can be several hexes across, and still make for significant terrain pieces (especially if they have rings and/or moons). Speaking of moons, Luna would be somewhere between 36-41 hexes away from Earth on such a map, depending on how close to perigee or apogee it is at the time of the encounter. In contrast, Mars at its closest approach to Earth would still be 5576 hexes away!
So, rather than fighting across the whole star system, battles will generally be fought a bit more locally.
In terms of terrain,
SFB,
FC and
Starmada all have various kinds of rules for terrtain types; fighting in a nebula, an asteroid field, even near the ravenous maw of a black hole!
When it comes to stealth and cloaks, there are two unrelated forms of protection at play; Orion strealth coating (a form of counter-measures which only applies when they are uncloaked) and the use of the cloak itself.
Stealth coating is handled pretty simply in
FC and
Starmada (where it uses the pre-existing Countermeasures rule); you adjust your die roll by 1 in whichever direction will give that weapon a worse result.
Cloaks are another matter. In
FC, you have a kind of partial cloak; you can still try to shoot at a cloaked ship, but at a significant penalty. In
Starmada, you have a true "hidden cloak"; you cannot attack a cloaked ship unless you first "detect" it (which can happen during each movement phase while the ship is cloaked; you roll a die and if the result is less than the number of turns the ship has been under cloak, the cloak is pierced and the ship detected. However, the cloaking device is still active, so even a detected cloaked ship still has to de-cloak in order to operate normally.)
Actually, if you want to see what the relevant
Starmada rules are like, the
Klingon,
Romulan and
Alien (which expands upon the Orion, Tholian and terrain rules available)
Armada rulebooks are available on e23.