We need more ap-stats. My thoughts on improoving ap-itemisation

I've seen a lot of people blaming one particular item: or , etc. But I think the probleme is much more profound. AD itemisation needs a lot more different stats. AD, AS, lifesteal, critchance, lethality,... AP itemisation revolves only arround AP. Ever since the season 5 mage update cooldown reduction has ceased to be an optional stat, but a nice little extra candy you get regardless of what you buy. (Though I don't think it's bad to have a lot of cdr all the time). Mana is not directly impacting the damage output anyways and becomes a decorative stat past the 20 minute mark, unless you play kassadin. So we need more stats that impact the magic damage output. Or make already existing stats more meaningful. For example:

• Spellblade stat. Similar to nashors passive, but as a stat that can be aquired with several different items: Magic dmg upon AA.
• Hextech stat, amplifies effects of hextechitems
• Item that enhances spell damage based on mana. (And change that the mana build path not results in tons raw ap)

I know these suggested stats might seems weird, but with adding more different stats that directly affect how mages fight we could at least get away from ap-items only competing in how much ap they give for their price ( : 100 ap for only 2900 gold... any better offers?... 3,2,1 sold)