If you suicide to Revive, you're doing it wrong.
OP, you seem to completely underestimate the value of a Lux and what her role is. As a guy who mains Lux on SR and playing her occasionally in Dom, I would never classify her as a support.
A Dominion Lux is best played with Durability, CDR, and Mpen rather than flat AP. This gives her exceptional Turret Defense and Harass capability, considering her range. Her offensive ability solo is subpar, but with the group she is a team asset, providing hard and soft CC, a weak but noticeable shield, and the range to catch stragglers. Most champs are hard-pressed to escape from or chase a Lux.
Additionally, despite "okay" ratios and not building flat AP, she does not much lack for damage, she just needs to proc her passive. A Lux who does not properly use her passive is a bad Lux.
And I would be remiss if I did not mention the 24-second Ult, Bane of Backcappers, Death of Fleeing Champs, Denier of Storm Buff, Defender of the Bottom Lane. It has a short as hell Cooldown, abuse the hell out of it.