What was the real reason for nerfing soft leashes?

Riot has constantly been talking about champion diversity and how they want the jungle to be open to a broader spectrum of junglers. I really enjoy this idea and I think many others like the idea as well, not just limiting the jungle to assassins, for example. However, with this nerf Riot has actually taken out a lot of junglers out of the pool. A lot of ranged junglers relied on the soft leash so they could take minimal damage. This nerf on top of the stronger jungle mosnters this season has resulted in ranged junglers taking huge amounts of damage. Some can't even do their first clear which ultimately goes back to my point, being that a lot of ranged champions were taken out.

There wasn't any reason to take out ranged junglers from a player's perspective. They were uncommon in the jungle and were by no means "overpowered".

One of the best examples I can come up with is Twitch jungle. Twitch jungle was a playstyle among the lines of Shaco/Evelyn. I personally used Twitch jungle a lot in S4, being in the mid-Platinum range at the time. Twitch was a ranged jungler that heavily relied on the soft leash to be successful in the jungle. Invasion from the enemy jungler was always dangerous for this sort of playstyle, and you really had to play your cards right or you could fall behind easily. Twitch jungle was especially good at ganking because of his long stealth and high damage. He was by no means overpowered because of the threat of invades and other counters. The biggest counter for any stealth champion such as Twitch would be a pink ward. Your enemy has to invest 100g to prevent a gank that normal wards can not cover as easily. This is perfect counterplay in my opinion. Twitch jungle had extremely good ganking capabilities but had counterplay to him.

However, when I first tried Twitch in the jungle this season with all the changes, I got decimated on my first clear barely making it through. When the 5.1 patch hit, Twitch jungle was completely destroyed. I played a game with him unaware of the changes and I could only clear Golems and Red Buff until I had to go back. I haven't tried other ranges junglers, but I assume for some of them it is not possible to clear anymore.

I think an easy fix for this would to be bring back soft leashes BUT have some sort of clearing penalty in return for less damage.

For example, if you brought back soft leashes to how they were but made it so if you were out of the "leash" range, your attacks had a chance to miss the jungle monsters I feel like that would be a fair exchange. I would rather have a slower clear time than to not be able to jungle with a certain champion at all. Slower clear times in exchange for reduced damage (soft leash nerf reverted).

This will have the largest impact on duo-lane partners who like to balance monster damage between them but will also affect long-range junglers who use the camp aggro range reset to take even less damage.

The fact that you have made the champion pool in the jungle less diverse has lead me to think that junglers have been impacted the most, not the bot lane. Theoretically both bot lanes have the opportunity to take the Small Golems/Gromp, so I don't believe this was a balancing issue for the bot lane. One may argue that if a lane swap were to occur, the side that stays bot can take that jungle camp. Most of the time that won't be the case since the jungler usually starts wherever their bot lane is to get a better start on their clear. It is also ultimately the player's choice, so if one side decides to lane swap, that is an opportunity they lose if they choose so.

The patch notes didn't really go in depth and were sort of vague as to why Riot decided to nerf the soft leash this hard, and so I really want to know the thought-process behind their decision.

TL;DR I believe Riot has taken some diversity out of the jungling champion pool as a result of the soft-leash nerf. I believe the best solution is to bring back soft-leashes in exchange for slower jungle clear times.