Alright I’ll address those issues
Definitely not the way to go, this would make it so much less enjoyable. If you pull off a great play, not spawn killing/camping, this would absolutely ruin it.
A much better solution would be to make that damage boost(after getting spawn killed a while), take affect sooner, maybe by just 1 kill.
I wouldn’t necessarily call this a problem. Although with the lack of items, it makes it a lot harder to outplay the other team.
Id honestly be fine with this, because these new maps are huge. 
As long as flag holders can’t use them, and can’t be used during combat.
Edit: It should be the leap from blockdrop**, so we can go up, down, whatever direction instead of just straight forward.
Now when buying this would this replace the bow, or be a separate item? If it’s a separate item I’d be down for it ig.
Diamond is a no because it wouldn’t do anything besides make fights longer, making stalemates even worse.
Poison arrow is a no, the damage ticking would be awful, and the crossbow is already a buff to bows.
If it was the sword from skywars, and included a new team upgrade that puts some fire protection on your armor, I’d be okay with this.
Now an item I’d love is the lasso, you can read about it here. I know it’s not a suggestion for ctf, but it would still be a great item for ctf too imo.
Now I do still agree with Absurd, they should fix the current mechanics instead of adding more. With adding a few items. Ohhh I remember another thing, after buying an iron sword, the diamond sword should be cheaper, maybe not 100, but 150.