Take my view with a pinch of salt because I've not seriously thought about the editorial guidelines until I happened upon this discussion in the recent changes.
I pretty much agree with @Forte, in reading an article the info can be relayed to the user more elegantly/naturally. I also think it would be unnecessary to apply this standard to every individual (correct me if this is not what you are suggesting @PrimersophiaXVII) because the majority of individuals here are historical and did not even know about the T in LGBT, so the information would basically be redundant.
The idea of Lenin's infobox reading
- Vladimir Ilyich Ulyanov (22 April 1870 — 21 January 1924) (he/him)
seems ridiculous, because transness has only become well-known quite recently, so his gender as a historical figure is self-evident. Now perhaps there are a couple exceptions where it would make sense because a person was especially involved in that field, in which case I think the article text itself would make it pretty clear anyhow. I don't like the idea of creating a standard which would be rarely applied - inconsistency leads to confusion.