/gamerule itemCooldownTime <time>

There are a few items in Minecraft that have a little cooldown, like ender pearls, shields, and the flint and steel, and the cooldown time of these is inaccurate but that's not a matter.

Therefore I think that an 'itemCooldownTime' and/or a 'doItemCooldown' could be a great idea.

For example, with this, you can decrease or avoid in-PVP ender pearl spamming; or remove the problematic shield's cooldown.

The gamerule syntax could be something like this:

/gamerule itemCooldownTime <CooldownDelaySeconds>

/gamerule doItemCooldown <true/false>