My own input, based on other voices I've heard:
On a personal level, I'm always honoured to see a shrine of mine nominated, and don't really mind votes on my own shrines being split if there's more than one in the poll.
However, while I understand that we're voting on shrines rather than members, I think that if a person has several shrines in the poll, voters would not allocate both their votes to shrines by the same person and instead spread them out - understandably so, to give credit to more than one shrine maker. And in that case, people with multiple shrines in the poll aren't at an advantage, but the opposite, since votes on their work would be split. As said, that doesn't bother me, but I can understand how it may bother others, especially since I know that winning a Shrine Spotlight award can be very motivating (and that doesn't imply that someone "takes Spotlight too seriously").
As an aside, while I don't see multiple shrines of a person in a poll as an issue in terms of "being at an advantage" (since I don't think it gives anyone an advantage), I think it'd be nice to promote and reflect the diverse shrining styles in the nominations (it is called "Spotlight" after all) by way of encouraging shrines by different people to be nominated.
I don't see a hassle-free way of implementing a hard limit of 1-2 shrines per person without making the nomination process unenjoyable (none of us would want to limit it to "first nomination sticks, nobody else can nominate a shrine by the same person"), but I'm in favour of Jae's suggested soft cap. :> Add a line in the Spotlight about promoting variety, set a soft cap of 1-2 shrines per person (depending on outcome of the dicsussion above), list any nominated shrines by the same maker next to each other for visibility? Something like that.
are part of the elements that compose a person.