Yeah, if you build with an escort in mind the regent is the better choice.
If you want to tank well in the Sovereign, your entire skill tree needs to be reworked away from being damage dealer and an engineer does it better of course., but a tac can do it, too.
Make sure you max shield and armor over weapons, get skill points in hull and shield repair, damage resistance, etc and use gear accordingly. Then take a look at skills.
At some point you will be able to get chased by the entire KDF and not get killed (unless they power drain you to oblivion).