So this is a pretty hot topic right now in the community and some cool suggestions like a stack limit of 3 has been mentioned as a possible solution.
Something however that has been somewhat overlooked is the state of innate flash farming carries (dusa, sven etc) vs heroes lacking farming tools (riki, ck).
With the rework of Clinkz he became a more well rounded hero for sure but he also in my opinion lost his identity. It worries me going forward and I hope valve will seek different solutions instead of homogenizing the hero pool for the purpose of viability.
What I currently believe is the biggest offender in this situation is the design of the jungle. Lots of changes has happened between 6.8x to the current jungle but can be summerized as:
Lower creep bounties but higher density
This is what I believe is the reason the disparity exists between the two archetypes. Flash farming is simply too rewarding since the amount of farm on the map is rarely a limiting factor for these heroes anymore. It's not uncommon to see luna/medusas with 500+ cs at 30 mins and at the same time each creep worth less than in older dota further punishing slower farming heroes.
I don't mean for this to be a "I hate change type post" as for the most part I think dota has gotten better and better. But I think the jungle is where problems do reside.
Sorry for rambling and would love to hear what you folks think!
Source: https://www.reddit.com/r/DotA2/comments/plucsm/stacking_jungle_meta/