It’s just as bad as your English.
You really don’t listen...I can confirm that tnt/cannons are the cause of any existing lag.
Everything else (other than redstone/tnt) is optimized and the server runs 20tps @ 300 players.
Just to reassure you, cannon fixes and making sure they don't affect performance is our top priority, just above finishing prestiges, quests and some other small tasks.
@Mephen has made significant progress with "LemonSpigot", the new jar we'll be running. As a bonus we've also added the following to it:
Even if it seems like we're not doing anything, there's a lot going on development-wise.
- Async Hit Detection Packets
- Kohi Knockback Values
We'll see about @Mephen posting a developer post to go into more detail about this.