borrowing → bor
When the {{label}} → {{lb}} vote passed, I posted a request in the BP and you volunteered to do the change, that's why I came here directly to you to see if you would like to convert the {{borrowing}} → {{bor}}. I disagree with your idea of leaving shortcuts as shortcuts and long forms and long forms, but feel free to decline my request, I'm OK with it and I intend to post a request in the BP later. (I should learn how to run a bot by myself!)
Re: "The shortcuts are redirects to longer forms. If we're not going to allow the longer forms, why even have them?" Allow me to try and give a rather long answer.
I don't know, I suppose having both redirects and longer forms was your idea? I don't exactly care about having "short template name" -> "long template name" redirects as long as people can agree on using only the short forms in entries. I mean, I believe you decided exactly all these redirect names, but I didn't check one by one: {{m}}, {{l}}, {{ux}}, {{der}}, {{bor}}, {{inh}}.
WhatLinksHere for {{inherited}} in the main namespace = 35,082 entries. WhatLinksHere for {{inh}} in the main namespace = 34,922 entries. {{inh}} redirects to {{inherited}}, so it follows that at least 160 entries use the longer form (0.45% of all entries). The difference between {{inh}} and {{bor}} is that {{inh}}/{{inherited}} were created together and mostly nobody is using the longer form; and {{borrowing}} existed for 5 years before the {{bor}} was introduced, so we used what we had, but {{bor}} became popular quickly,as evidenced by the approximately 40% 66.6% of entries using {{bor}} rather than {{borrowing}} (the actual entry count is in the borrowing → bor vote) and the fact that the vote passed.
Still, as I said you don't have to do anything. I was not trying to convince you to change your mind, I just said what are my thoughts about the points you mentioned.