User blog comment:Emptylord/Class Reworks - Itemization Follow-up/@comment-28280538-20160512201236/@comment-3974211-20160514162750

If you want an "offensive defensive" item, then the effect should either reward you with offense for doing something defensive - or the opposite. For example, if the version I've proposed stole magic resistance (similar to Wit's End); or to add Odyn's Veil, where you store damage taken and then unleash it (the shape could even be changed to a skill shot). Having an item that just grants both stats can never be viable without all champions being required to buy it to compete with other people that have it.

In a separate project I reworked Quicksilver into an activated spell shield that builds into Banshee's and loads of other items, including a new Moonflare Spellblade that gives you an offensive active if you block an ability.

Turning the movement speed into a Dead Man's Plate is definitely an interesting idea....