I've noticed that most people here seem to favor having all ships travelling at the same speed however doesn't it make more sense to have ships that have varied speed based on their role?
A simple categorization that seems to make sense is that of battleships, carriers/cruisers and destroyers.
Battleships can be really slow since they are intended to defend or attack targets that are basically stationary (e.g. planets) at very long range. By reducing their speed they can mount much more fire power. They also can be much tougher against other long range opponents since they can have thick armor and are less prone to being blown up by a luck hit because they have fewer engines.
Carriers/cruisers travel at 'standard fleet speed'. They are essentially the standard threat response force with battleships being brought in if there is something they can't handle.
Destroyers are designed to be significantly faster so to be able to run down enemy ships of a similar tech level and to be less vulnerable to being caught by opposing ships. They also tend to provide scouting and sometime target acquisition for battleships since they can carry big sensors while still being fast enough to run if they see something they don't like.
How a fleet is distributed between these classes would adjust based on what sort of threat is being faced.
e.g. No threat and just expanding/scouting -> mostly destroyers. In contrast to, war with evenly matched enemy -> lots of battleships at key systems.
Does anyone else do something similar?