Possible changes to Debian's decision-making processes

You can essentially think of their voting system as a topological sort over the graph of preferences. If a majority prefers X over Y, then draw an edge from X to Y. Then, hopefully, you have a DAG, and if you do have a DAG, you should* have just one source vertex, so hopefully, you can just pick that one source vertex as the winner. This is not very complicated all by itself and can be simply explained as "pick the option that would beat everything else in individual runoff elections."

Most of the complexity comes down to "what if there's a cycle?", in which case you have to drop one or more edges until there isn't a cycle anymore. Debian's system is designed to drop edges in such a way as to invalidate the lowest total edge weight overall (where the weight of an edge is the total number of voters who prefer one option over the other). There are numerous other ways to do it, and you can go off into long tangents about the mathematics of it all, but suffice it to say that 1) there's no "perfect" option (for a rather technical definition of "perfect") and 2) Debian's choice of system is reasonably sound compared to most or all of the alternatives, because its flaws are relatively minor, technical, and difficult to exploit.

* In principle, you can come up with some weird edge cases where e.g. everybody votes for X and Y over Z (and all other options), but "X is better than Y" receives the same number of votes as "Y is better than X." Then you can't draw an edge between X and Y at all, and you end up with two source vertices (X and Y are effectively tied). As you might expect, the Debian constitution actually does account for this possibility, but it just says that "the elector with the casting vote chooses which of those options wins." The only obvious alternatives would be to pick a winner randomly, or to automatically pick "further discussion" (which basically means "nobody wins, now go find some new candidates and start over").