I'm torn on the new items Riot is coming up with. They are more complex, adding diversity, keeping the game "fresh" in some way, but the complexity could backfire, could drive away new players, could make things a bit frustrating. I liked how LoL mainly focuses on TEAM play and strategy, these items could turn things into a rock-paper-scissors game.
Look at Runeglaive, there's a reddit thread going on now showing it turns Nasus Q into magic damage. Runeglaive is also receiving a buff on PBE, thus it should become a pretty strong item on Live sometime soon. Assume Nasus stacks Q most the game as AD damage, players build armor to counter, then late game he builds Runeglaive and bypasses all the armor you bought. Of course the tradeoff is he has to take Smite instead of TP or Flash.
The new Devourer on PBE looks crazy. Nightblue was jungling Vayne. At 30 stacks the item becomes "Sated Devourer: When Sated, every other basic attack will trigger on Hit effects twice." Jungle Vayne new meta?
Zeke's Herald is going to be another game changing item currently on PBE.
Of course strength in this game has always been measured by items, but some of these new effects don't seem to take into account the 120+ champions already in the game and what potentially could happen when you start modifying their abilities beyond just more AD/AP.
+AD/AP was a very basic & simple measurement, these new items are modifying abilities beyond their intended design. The affects can't be fully parsed before they hit Live. The meta can be shaken so easily by any of these items if tuning is off just a smidge. It could easily become another Black Cleaver 2.0.
Again, I'm not necessarily against any of them. New items are fun. But we might be losing a bit of the simplicity.