As I understand, tiles on GalCiv maps represent time, not distance; the idea being hyperdrive is magnitudes more effective when farther away from gravity sources.
parsecs are a unit of distance (3.26 light years to be exact), so yes, the tiles on the map represent distance and not time. Habitable planets are generally not located 6.5 light years or more from their host stars.
while i don't have access to the relevant quotes atm. I believe it has been stated several times that yes you travel more slowly when close to large masses (sun's/planet's) that's why planets are spaced so far it takes approximately the same amount of time to move 1 tile in a solar system as it does to move 1 tile outside of a solar system even though the two tiles are not technically the same size
so in game they are treated as the same distance for simplicity of mechanics while lore wise they are not the same
thus since they don't represent distance it is more appropriate to measure them in time
edit
i found one quote that hints at speeds relating to (suns/planets)
this is from a galciv 2 tech description impulse drive
The 'fold' in space, which depends on the mass of the ship along with nearby mass concentration,"
and i also found this and thought it was humorous although not related
from the tech new propulsion
so Hyperdrive used immense amounts of energy in order to slightly warp space to make a 10 million mile trip seem the same as taking a one light year trip.
one light year is equal to just under 10 trillion kilometres (or about 6 trillion miles)
making a trip seem to take 600,000 times longer doesn't sound like a good idea to me
Someone will likely make a mod to do this, so how about we don't handicap the players that would not like this insanity? Sorry, but I like not having to build a starbase every 15 spaces just to get from one system to another.
i would definitely be downloading such a mod