aha: I should've asked for this myself. A couple things wrong with it:

1. the dws() routine shifts @array instead of @_, so all code that ran after it (everything but danger()) was passed an empty @array. This is the big source of differences.(dws() also needs fixing to return the actual buckets).
2. the repson() routine does a my @array = shift when it should do a my @array = @_ (only affects its own standing).

below are corrected dws() and repson() routines, and I've taken this opportunity to include a fix for my silly holdover in my danger() routine:

sub dws {
    my $nbuckets = 3;#shift;  # number of buckets to divide @array int
+o
    my @bucket;        # @{$bucket{0 .. $nbuckets - 1}} are the bucket
+s

    foreach my $n( 0 .. $nbuckets - 1) {
        foreach my $size (1 .. int(0.9999 + @_ /($nbuckets - $n))){
            push @{$bucket[$n]}, shift @_;
        }
    }
    return @bucket;
}
sub repson {
    my @array = @_;
    my $num = 3;                    # buckets

    my $cnt = @array;               # total items
    my $base = int($cnt/$num);      #  }
    my $left = $cnt % $num;         #  } $cnt = ($base * $num) + $left

    my @buckets;
    for (1..$num) {
            push @buckets, [ splice(@array,0,$base + ($left-- > 0 && 1
+) ) ];
    }
    @buckets;
}
sub danger_fixed {
    my $buckets = shift;
    my @list    = @_;
    my $mod     = @list % $buckets;
    my $inc     = int(@list / $buckets);
    map{ [splice @list, 0, $inc + (--$mod >= 0)] } 0 .. $buckets - 1;
}

relative results:

           Rate  dws tilly   eg fast_sp2 tillyr danger repson fast_sp1
+ danger1 fastolfe
dws      1034/s   --   -1% -18%     -32%   -34%   -36%   -36%     -40%
+    -42%     -52%
tilly    1043/s   1%    -- -17%     -31%   -33%   -35%   -35%     -39%
+    -42%     -52%
eg       1263/s  22%   21%   --     -17%   -19%   -21%   -22%     -27%
+    -30%     -42%
fast_sp2 1516/s  47%   45%  20%       --    -3%    -5%    -6%     -12%
+    -16%     -30%
tillyr   1564/s  51%   50%  24%       3%     --    -3%    -3%      -9%
+    -13%     -28%
danger   1604/s  55%   54%  27%       6%     3%     --    -1%      -7%
+    -11%     -26%
repson   1613/s  56%   55%  28%       6%     3%     1%     --      -6%
+    -10%     -26%
fast_sp1 1723/s  67%   65%  36%      14%    10%     7%     7%       --
+     -4%     -21%
danger1  1796/s  74%   72%  42%      18%    15%    12%    11%       4%
+      --     -17%
fastolfe 2174/s 110%  108%  72%      43%    39%    36%    35%      26%
+     21%       --
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