I think the DT1 list would be nice with around 50 members on it anyway..

At that point abuse would be somewhat noticeable and keeping track of every DT2 will be difficult.

I like LoyceV just fine but 6X as many votes as SaltySpitoon? lol no..
Is LoyceV 6X more trusted to make good votes than SaltySpitoon?

These votes have nothing to do with how trusted someone is. Stop confusing concepts.

Does the algorithm decide "most useful" before taking into account how many exclusions a member must overcome to stay on DT1 or after?

Exclusions are processed at the very end.

That is no good IMO..
What about all the extra votes someone needs to overcome rivals exclusions?

Nothing about them. If you're excluded, you're excluded.