straightarrow
* Since there is no spoiler effect, you could just let everyone on the ballot. Letting abstentions count as zero votes, obscure candidates cannot win. (Less severely, abstention could count as a fractional zero vote, i.e. 0 in the numerator of the average and 0<x<1 (say x = .25) in the denominator...)
* Or require a certain number of signatures to let a candidate on the ballot.
I'm not sure I understand your comment. There is no "instead" -- you can vote honestly for both your preferred candidate and the popular candidate.
For example, adding an additional candidate should not affect the average score of the rest of the candidates, hence there is no problem with "independence of irrelevant alternatives". (I leave the rest of the conditions as an exercise to the interested reader.)
That having been said, all voting systems can be vulnerable to strategic considerations. However, simulations and theory suggest it's much less the case for score voting compared to ranked choice systems. See electology.org for some pointers to research.
But I have good news: we can steer a more stable course with score voting.
Score voting doesn't violate Arrow's Theorem (because it's not a ranked-choice system).
Here's how it works:
* Each voter gives candidates a score from 0 to 1.
* The highest average score wins. (The average can be weighted to account for abstentions.)
The upshot:
* No political parties are needed.
* It resists gerrymandering because it's non-partisan.
* If there's a bias in the system, it's towards the center.
* Simulations indicate score voting is socially optimal.
* Arrow, himself, expressed preference for approval voting (a variant of score voting)
Further reading:
electology.org
en.wikipedia.org/wiki/Range_voting