Offensive power factors in whether the weapon has any chance of hitting. For Sentinels, that chance is nonexistent except against people deliberately taking hits or those who are unaware that they are armed.
If target is in range, it hits. That the sentinel lacks the range or speed to make range a non-issue is irrelevant (to me, which is why I consider sentinel high defense, higher offense). Actually, it is a good thing sentinel is slower than player, because if not, that fracture cannon will destroy the player.
Is that a desirable mechanic? Should an exploit that provides no excitement or challenge be (effectively) the only way of defeating an enemy ship?
Maybe, maybe not, but it is different than others. For previous enemies, player can skip almost every enemy then backtrack and smash with overleveled equipment.
And kiting sentinels is not broken or even necessarily an exploit, even though you (JBW) seem to think it is.
Download and Play in 1.9 beta 1...
Drake Technologies (Alpha): More hardware for combat in parts 1 and 2!
Star Castle Arcade: Play a classic arcade game adventure, with or without more features (like powerups)!
Playership Drones: Buy or restore exotic ships to command!
Other playable mods from 1.8 and 1.7, waiting to be updated...
Godmode v3 (WIP): Dev/cheat tool compatible with D&O parts 1 or 2.
