Make table headers stick to the top when scrolling
Rename tables IDs and classes
Left align columns with numerical data

[Reasoning for this UX guideline][1]

[1]: http://blog.editage.com/Aligning-Columns
Add right padding to the index tables

I don't like the fact that I'm adding a padding to each cell
individually. Ideally, I'd just pad the table, but if I do that, then
the header line separator will be a little shorter. I like the way the
line separator is set up at the moment, so this right padding will do
for now.
Add basic highlight effect to the header of the sorted column
Allow up to two duplicate method calls

This is mostly due to Rails' idiomatic response block:

    respond_to do |format|
      if success
        format.html { redirect_to some_path }
        format.js { head :ok }
      else
        format.html { redirect_to :back, status: :bad_request }
        format.js { render status: :bad_request }
      end
    end

I also don't see the harm in calling a method twice if that method uses
some kind of memoization or returns a simple value.

This Reek smell seems useful but maybe I should just turn it off.