As was mentioned before, one round of trigger NMs will net you eight Kirin pops. The drop rate is not nearly as bad as you make it out to be. Your LS must have had the most horrible luck I've ever seen if it took you years to get the first Cuisses (or you only did it twice in those years). Wiki states a ~25% drop rate with a very high sample, my personal experience has it a lot higher still. Over years of doing sky, we got about ~40% Wyrmal Abjuration drops off Kirin. Now, even if you go by Wiki's lower estimate, with eight Kirin pops from one round of trigger NMs, you'll get an average of two Wyrmal Abjurations from one tour of sky farming, which can even be done in one day.
Trotter Boots. And they have the worst drop rate of all movement speed items I'm aware of, including Strider Boots, from my personal experience.
It's not the same, but any movement speed bonus over 0% has a major advantage: it allows you to outrun the majority of mobs. So while it's not the same, it can be used for a lot of the same things, especially during battle (kiting was mentioned, especially in combination with PDT-8% on them).
Was mentioned a few posts above yours.
It's about efficiency. Movement speed bonus saves you more than than you think, and not only by running. As I mentioned before, the "outrunning mobs" part makes it possible to run through almost any area without Sneak or Invisible, which saves you more time casting, especially in zones like Ro'Maeve where there's magic aggro all around, even right at the start, and additionally it saves you having Monomi and Tonko tools in your inventory, which is a major plus for me. It's also very useful for kiting, if there still are such battles. And ask a BLM75 what they could do back then with Herald's, you'll see quickly that the price tag is not just due to its rarity, but actually mainly due to its function. BLM with movement speed was godly back then.
And it's only Sneak and Invisible that got an upgrade if I recall correctly, Monomi and Tonko still only last 3min for Ichi and 5min for Ni, same for Spectral Jig, which is still retardedly short.