"Take the same amount of money that would have been tax deductible and instead distribute it to parties on a per-vote basis."

Horrible idea.  Distributing funds for an election based on the results of past elections gives the incumbent government an unfair financial advantage over their opponents and completely disenfranchises new political parties who didn't participate in the previous election.

Tax deductions for political donations make donating more attractive for the middle class and people on a fixed income if they know they will get some of it back in April.  Rich people don't care about these tax credits.  They will donate the full amount regardless because they have that much more disposable income.

If anything each political party should get a flat amount from the government for each candidate they are running and that is all.