The Nashor's vs Lich Bane dilemma

While I was trying to pick which item to build on my top lane Diana between and and looking at the item's stats in detail, I realised that both of these items gives stats that are more beneficial to the unique passive of the other item. Let me explain. . . . gives a burst of damage every time you use one of your spells. This means that CDR is a huge asset to anyone who wants to build a , but sadly, it doesn't give any CDR. On the other hand it gives a pretty high amount of bonus movement speed, at 8%. gives you more magic damage on every auto attack and gives you attack speed, allowing you to proc it more often. Since it gives you more damage on every attack, obviously movement speed is an asset to anyone with a since you can actually follow someone around and proc it on them alot. also gives 20% cdr, which is a ton of CDR for an item that isn't necessarily build by people concerned with CDR. . . . Wouldn't it make more sense if, say, didn't give movement speed but gave 10% cdr (or 20%) and gave either 0 cdr or 10% but actually gave 5-10% movement speed? Of course the stat values and prices of the items would be reevaluated to take these into account.