On-hit item

How come all of the on-hit items besides one give attack speed? Some of my favorite champions to play use on-hit items, but it's actually too easy to go over the attack speed cap. Bork+Rageblade+Bloodrazor have great synergy in theory, but they give you over 148% attack speed. Add in runes+masteries and you're usually at 166%. Factor in that most on-hit champions have some pretty impressive attack speed steroids and you suddenly shoot over the cap before you know it. For example, these three items put Master Yi over the cap during his ult without even building another attack speed item such as Greaves or Wit's End. Titanic Hydra is an ok item choice, but it would be nice to have more similar options.