Offense/Defense/Flex Is Just a Watered Down and Dumbed Down Version of Old Runes
I like the idea that we now have more choice in how we build our rune pages depending on what we play and what we play against, but these choices are both limited and lackluster compared to the options previously offered to us.
The ability to mix and match. The ability to pick between scaling and flat.
In fact, here's a more complete list of options previously offered to players that will make the new choices feel like a gut torn piece of the past.
http://leagueoflegends.wikia.com/wiki/List_of_runes_(Historical)
Some things I enjoyed doing with runes was combining flat AD with Armor Pen (or Lethality later on). And for yellows, well, everyone knew flat armor was best...in fact, we got 9 armor just for dedicating our yellow slots to armor alone, which left us with options for reds, blues, and quints. Well, blues, I'd generally choose between MR or a mix of scaling and flat CDR. And quints, well, who could say no to +4.5% movement speed? Not this guy! But...actually...I could, because sometimes I wanted more damage instead or a heaping helping of flat CDR if I happened to NOT want to buy so many CDR items in game.
Point is. You might think the changes give you more choices. But, the truth is, it's just a dumbed down and watered down version of what players were once offered.