Analyzing why high elo and LCS diversity sucks in the Jungle.

The biggest factor in jungle stagnation is the reliance on clear speed and safe early pressure on the enemy team above all other factors in competitive jungling. This is due to the Min/Max nature of competitive play and the mechanics of the jungle. The jungle is the only place where it is possible to increase the amount of gold and experience in the game without having to kill enemy champions. In lane there is only as much gold and experience as the minion spawns allow. In the jungle the faster you kill camps the faster they respawn meaning more gold and more experience is available.

The ability to tap into this gold advantage and experience advantage ought weigh almost all other factors when LCS level players choose junglers. It creates an environment where very little variation in clear speed is allowed. Unless a jungler is blatantly OP like Sejauni at cinderhulk release (which by default means they will be getting items that increase their clear speed) there is no advantage that outweighs the lost gold and experience.

There is a clear pattern to the junglers that have been constantly picked in competitive play in the past two years.

and tank

All of them have fast early clears (or did some have been nerfed heavily) and could reliably counter any other jungle pick by harassing, invading or simply out leveling them. Unless you would like to see a comprehensive series of nerfs that leave all of the above champions much weaker (and in the case of Nidalee, Elise and Rek'Sai completely without an identity as all three are ONLY good at early clears and pressure) you will have to deal with the fact that LCS and high elo is going to have very little diversity in the jungle.

A long term solution would have to involve homogenizing jungle clear speeds significantly and increasing the late game potential of champions who fall off heavily. Its unlikely this will happen anytime in the next two years barring a massive meta shift and a shit ton of reworks and class updates so lets get used to seeing the same faces again and again and again.