It is arguably the worst path of any subclass and with the addition of Well of Radiance it seems even more worthless. In D1 you'd need two Titans to achieve the same affect as that super, so I have a solution. Make it to where you can shoot through the bubble and it gives a slight damage boost not as much as Well, but close enough. Well should offer more damage and bubble should offer more survivability.
This leaves the new commander path as useless, but just giving that a massive damage buff would justify using it over the new Ward of Dawn. (Even in it's current state it is worthless, since you do more damage by shooting) As it stands two thirds of Sentinel subclass are "useless" (very gimmicky) in PvE when they should be the strongest for the Titan. Either one of those would work, but both would be preferable.
[b][i]THESE BUFFS AREN'T MEANT FOR PVP[/i][/b]
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It would be too oP if your allowed to shoot through bubble. There should be a downside to this like you'll deal less damage when shooting through bubble. As for the damage buff there's no need for it. Defender is built for defense not offense so instead of weapons of light. Give it armor of light. In the end of the day your sacrificing offense for defence.