In two recent Tweets, Teamfight Tactics Lead Designer Mortdog has revealed some major changes that will soon be implemented on the PBE (Public Beta Environment) with the hope that player feedback will help determine whether or not they will ultimately make it onto the game's main servers.
The most significant change is to Grievous Wounds, which is an anti-healing property applied by both the Morellonomicon and Red Buff items, indicated in-game by a heart with two crossed sabers in front of it that appears above affected champions. Currently, both items nullify any and all healing, while the planned change will still allow for 20% of healing effects to apply to affected heroes. Both items are also receiving an increase in damage but that lasts over a much longer period of time. Mortdog has explained that both of these items are generally applicable to most, if not all kinds of team compositions, and these changes are in hopes of altering their utility to more of a case-by-case basis.
Blood Thirster and Hextech Gunblade, both items that heal champions based on damage dealt, are also receiving nerfs to the amount for which they heal. These items are currently extremely powerful, with Blood Thirster being a must for always-popular Hyper Carry Draven comps, and many current changes seem to be targeting Draven comps specifically.
Additionally, on the newest Patch 9.16, Shapeshifters have become a lot more powerful due to the addition of a new Hextech Shapeshifter, so a nerf to Tier Five Shapeshifter Swain's healing ability may in hopes of making Shapeshifters a little weaker. Noble healing is likely being reduced for a similar reason, as 6 Noble comps have quickly risen to the top of the meta.
Assassins are also going to see a significant overhaul in a major reduction of the Critical Strike Damage buff they receive as their class bonus. Currently, three assassins grant +125% Critical Strike Damage while six grant +350%. These numbers have been reduced to 75% and 150%, however, with the addition of an increased Critical Strike Chance of 10% and 25% respectively. This is "DPS neutral," Mortdog explains, meaning that theoretically, assassins will still do the same amount of damage with class bonuses applied, just from a higher number of less powerful Critical Strikes.
Assassin movement has also been revamped, but without a visual example, players will have to journey onto the PBE themselves to see just how, alongside the ways in which these other changes will shake up the game.