Regardless of country, the most democratic system ever would be to allocate electoral college based on the percentage of your overall income you pay in tax.

Earn $50,000 pay $5000 = 10 college votes.
Earn $1,000,000 Pay $0 = 0 votes
Earn $100,000 Pay $25,000 = 25 votes. etc. etc.

The people then paying the largest percentages in tax get the biggest say. Non-producers (aka "spongers" in the UK) and Non-Doms (aka Tax-Dodgers in the UK) would get a whole lot less say.

The problem is, as you say, there are so many tax dodgers and spongers that put the current people into office, they are hardly going to change to a system that would see them out on their collective ears for offending the decent proper people that make up the ever-strained backbone of the western economy, not just in the US.