Tower Shield for 5th Edition

Tower Shields are something I miss from earlier editions of D&D. The idea that someone might want to wield one of those ridiculously large, bulky and heavy things appealed to me, and although few characters I have DMed for bothered, it always irritated me that they didn't re-appear....

...Well, now they've re-appeared (though to use one properly you will need to take a feat)

Armour Class
Tower Shield
Str 18

* If you are proficient with the shield you can, as a bonus action, set it steady and hide behind it, gaining ½ - ¾ cover from attacks that originate from the other side of it. As long as the shield is set this way, your speed drops to 5'. As a bonus action you can return to using it as a normal shield. Note: The cover bonus to AC replaces the normal AC bonus granted by the shield whilst it is being used in that way.

New Feat

Tower Shield Bearer
Prerequisites: Proficient with Shields
Benefits: You are Proficient with Tower Shields. Increase either your Strength or Constitution by 1 (Maximum 20). When you are conscious and using a tower shield, up to 2 adjacent allies gain a +1 bonus to AC, and you can use it to grant yourself cover (as outlined in the shield's description). 

Peek-a-Boo! I kill yooooou!