Btw, why exactly Event type?
How about next template:
Master. Put this card in play with 3(..5?) counters on it. Each time your minion plays an action card (or smth else) you may put it on this master instead, if there is no copy of that card already, and remove 1 counter.
If this master have no counters (some good benefit).
Any minion may add a counter to this card as {d} action, that costs 1 pool.
Increases diversity of cards, but not necessarily strategies.
A bruise-and-bleed deck from one clan or discipline set only have only one or two options available to it, due to the restraints of that particular discipline. A Malkavian S+B deck has many options. Yet few people are wowed by a deck playing Govern, Scouting Mission, Dominate Kine, Mind Rape, Spirit Marionette, Computer Hacking, Laptop Computer and Tasha Morgan. The somewhat weaker deck doesn't necessarily want to fall back to Laptop and Tasha because it 'wastes' an action - Malk S&B cares somewhat less because it can pile Conditioning on top of any bleed.
The same applies if you go for - for example - action modifiers: Dominate, Obfuscate and Dementation have a metric ass-load.
By proxy/indirectly, a lot of the arguments that apply to Card Limits vs No Limits apply here - some of the very strongest decks in the game already have a multitude of options, and spreading out to a broader range of cards has a tiny amount of impact, and it's still just playing Dominate Bleed Card every action. The struggling deck often has far fewer options, which is often part of why it's struggling - it might have to pick an action that isn't quite right for its needs because it only has one bleed action in its arsenal, not five.
New Card Idea: Limited Movement
