XP per kill
XP per kill and early XP in general is kinda out of control. I think this is the root of the problem of having many games feel hopeless only 5-10 minutes into a game.
have a bad back timing early on, or get killed as a wave or 2 is approaching your tower and your game (lane) is basically over. You can then cower in fear of your lane counterpart and try to avoid them for the rest of the game.
The fact that opposite laners can have a 2-3 level difference 10 minutes into the game is really frustrating and despairing. i know "comebacks & snowball" kinda explain this problem, but the level difference specifically is what makes the snowball so unpleasant. I can accept weaker turrets (they feel better after 5.23), and even like that they promote pressing your advantage. The excessive XP gained from a kill, however, snowballs games way too quickly early on.
A player landing a kill already will gain an item advantage; the level advantage is excessive. Obviously, a player killing the other should become more powerful and typically be able to 1v1 from that point on; but as it currently stands, there is often no coming back. The extra uncontested creep waves of gold and XP + kill gold really seem like enough advantages from a kill.
However, in addition to these advantages gained from the player landing the kill, the dead player misses out on gold and XP from creeps--effectively changing the difference in waves farmed from 1-2 to 3-4 as a result of 1 death.
imo kill XP should take (another) hit. Or at least make the XP for kills and/or minions SCALE through the early game up to what it currently is, kinda like how in the past (i forget the patch...maybe season 4), early kill gold was reduced and scaled to standard values instead. Typically, if you die in levels 1-3, your lane is far beyond lost, and this makes many games feel hopeless and completely unfun as a result of 1 single mistake in an early trade or duel.