Presently the witness voting system multiplies the advantage of substantial stakeholders 30x over lesser staked voters

No it doesn't. Everyone has the same 30 votes, both big and small alike. Both stakes are multiplied to the extent that all 30 votes are used.

1 SP = 30 SP worth of votes
1 million SP = 30 million SP worth of votes.

There is no systematic multiplication of larger stake over smaller here.

What multiple votes (approaching the original full approval voting with unlimited votes) does do, among other things, mostly good, is a better job of translating the choices of the majority of stake into a full set of witnesses acceptable to the largest share of stake, and protected against smaller share attackers.

Given Steem's situation has evolved from when the founders held the stake they mined, and now that stake is no longer in the hands of the founders

I don't necessarily disagree with your point here, but realize that what you are proposing is enabling a sort of "attack" where the minority stake (about 40%) is given increased power, because in this case we've decided that the majority (about 60%) happens to no longer be owned by founders, and that is "no good".

That certainly 'feels' like a good thing in this particular situation, but it wouldn't feel like a good thing if the 40% were in the hands of someone trying to cause damage and the 60% were in "good" hands. The existing system is more secure because it would keeps that from happening; the proposed one would not.

Again, this could be an acceptable, even perhaps desirable, tradeoff, but don't fail to recognize it for what it is.