Here is my list:
Nerfs:
Lina(Fiery Soul): Instead of the gain stack for every enemy hit by the spell I wish to see a change that gives Lina only 1 stack per spell. So it's still the same easy-to-keep stacks if you have them but much slower to bring them back if lost.
Tinker(Laser): Instead of 100% miss chance for 3/3.5/4/4.5 sec. I wish to see a 100% miss chance for the next 2/3/4/5 attacks for 3 sec. Basically same power level on laning stage but not forcing you to buy mkb in the late game to counter his laser if you don't have BKB.
Riki(Sleeping Dart): We all know how annoying this skill is, on the other hand, the ability is fun and I hope IceFrog does not remove it from the game. Projectile speed from 1600 to 1200 (increase chance to dodge if you have a good reaction). Also cast range from 1000 to 750, for a chance to punish Riki when he tries to dart someone.
Arc Warden(Tempest Double): God I hate this guy, he fun, and he requires skill to use but it's so frustrating to fight against his "copy" when he just stays on base in safety. Instead of "Attack Damage Penalty: 50%" on 2000 distance I wish to see: "All damage penalty: 33%" on 2000 distance, and "All damage penalty: 66%" if the distance is more than 6000. So same power level if the player uses the copy in a fight directly and a significant nerf if he spams it from the base.
Ursa(Earthshock): Ability is fine, the shard is broken, and not fun at all. Hope IceFrog completely changes it somehow.
Buffs:
Alchemist(Unstable Concoction): Cmon it's 2023 year, skill can't punish you for 4-sec stun + damage if the enemy somehow silences/stun you or just hide in "fog of war" Also it looks dumb that hero just can't throw this "bomb" just on the ground, like why?) I really wish we have the possibility to throw a bomb in AoE on any point of the map. So basically same skill but now you can also throw it on the ground and if you do this then DMG and the stun duration are twice less. Also, dmg and stun duration are twice less on your hero if you for some reason can't throw and explode yourself.
Troll Warlord(Battle Trance): Really fun concept that turns your hero into a berserk that can't die and fight the first enemy he sees. But also really weak stats on this skill. It's so easy to control this hero when he presses his ult. I wish Troll gets a significant buff to this skill. Like 30/45/60% status resistance when ult active and also if a troll kills someone in Battle trance it increases the duration for another 3.5 sec. And also I think the cooldown on this skill can be a little lower, from 90/80/70 to 70/60/50.
Lich(Chain Frost): For some reason, this skill feels so weak every time I use it. In the good old times when dota was brighter and more simple, this ulti has a decent impact but right now it's so easy to counter, every core has BKB every support has glimmer, pos 3 makes lotus/pipe, and ult just does nothing. Just compare it to Witch Doctor stun, if I can choose what skill I want to have after 20 min of the game I always choose wd stun instead of Lich ult. My hope is for a dramatically reduced cooldown, from 100/80/60 to 60/40/20. Also jump speed need to be increased from 850 to 1050. And maybe the number of bounces must be infinite by default, why not it's so rare to see more then 5+ bounces with lich ulti, today everybody knows how to coordinate against it.
Chen(Divine Favor): Oh cmon just make this passive useful, it feels like a skill from Warcraft3, not from Dota2(2023 year edition). Maybe at least global, idk. Or full rework, but do something.
Shadow Demon(Disruption): I love this skill, I love the concept that countering enemy "physical" carry and saving your heroes from offense but for some reason, this skill is not that good offensively, and most of the time used for defense/save. Also, I feel like offensively this skill can also save enemy heroes by giving them chance to blink out after disruption and it feels weird. So I hope disruption will apply root for at least 1 sec after. Also, I think will be good if Shadow Demon gets the possibility to cast spells and items directly in the "disruption ball" so the effect will apply to the enemy right after he back from this purple ball(only SD can cast, not for your teammates), so you can cast hex/orchid or Disseminate/Demonic Purge on the enemy when he disrupted like you can cast shadow poison.
Source: https://www.reddit.com/r/DotA2/comments/10r9ni9/top_5_buffs_and_nerfs_you_wish_to_see_in_the_next/