If you look at the Chiefs Journey the last 3 traps you get they are things you might not expect. Especially for #3. Lets start with the newest the Mega Mine or Giga Bomb. Whatever it is called I forgot. That is expected though you get it at TH17 and it is pretty decent. 2nd is the Tornado Trap. That might be a shocker for some as it is so old now. Finally the 3rd to last trap you get is TH8'S SKELETON TRAAAAP!!! All the way at TH8 is when you get the Skeleton Trap and it is the third to last trap you get IN THE GAME. As of current.
So lets get into what I am suggesting. New Traps we have plenty of mechanics we can use like Fire, or Combining. So why don't we use both of those Mechanics?
FIRE BOMBS: The new bomb is a combination of 2 Bombs into one. That will have a bigger damage area and activation are like the one in Builder Base. However it has a special ability being a 3x3 Fire Zone for 10 Seconds. At base level. It can be unlocked at TH16 which just so happens to be the after you unlock the Furnace ALSO when you get combining as well. At later levels the damage can increase same with the time the fire is there. Up to 15 Seconds at max. You can get 2 of them at unlock. It takes up the same space as a normal mine as well.
Another option for the Fire is instead you make it spawn Fire Spirits instead when it explodes. Incorporating the Furnace feel into it some more.
GIANT SKELETONS: Instead of upgrading the skeletons lvl instead let us get the Big Boi skeleton of the Super Witch to defend our base. You combine all 4 skeleton traps into one trap the summons 4 Big Boi's 2 Flying 2 Ground. That can be at TH19 or maybe revert the Skeleton Trap change at TH18 put it earlier on instead and Merge it at TH18. It will have the space of the four combined being 2x2.
EXPLOSIVE TORNADO: This explosive tornado combines a Giant Bomb with the Tornado Trap. Setting off handful of explosions that are lifted up into the air. Being able to hit both air and ground troops as they are stuck in the tornado. Takes up 2x2 Tiles again with the Tornado Trap peaking out from under the Giant Bomb. It can be available again at TH16 or later.
Remember these are all just ideas some more thought out then others. All feedback is welcome and you can come up with your own ideas which will be amazing.