After discussing it in the Discord, I see that the reward penalty on rentals wouldn't solve this (though it would give a boost to ownership) and that the cooldown also wouldn't entirely resolve the problem.
@eldon1 put forth another interesting idea which is to reduce the energy cap to 25 (from 50), which I think is creative.
All that said, at the moment I'll be honest and say I'm not a fan of any of the ideas. I maintain that I think daily rentals are a utility that we shouldn't kill. My preference right now would be to not change anything.
What I'd love is for the company to look at this in more depth, with the data that is available to them (e.g. on rentals and NPE) in order to suggest a solution (if one is needed at all).
Reducing the energy cap is also not an ideal solution, I was just spitballing ideas but I really cant think of anything else. We are open to better ideas.
Or the team has to come up with an redesign of the way the energy and rentals work.
Yeah, I just brought it up here because I thought it was an interesting out-of-the-box idea.
I still think rented cards should have a cooldown to deal with this type of concerns:
I know is not directly related to the exploit we are talking about but its a concern for some people.
I really don't think we should be reducing the energy cap to 25 as it puts a bigger strain on players. As much as I don't agree with changing the rentals, this would have a worse effect in the game. We aren't a gacha game nor I think we want to be. I think it's great that players can play more in one day and not worry about Splinterlands on the next one.
I've updated my position on this: https://peakd.com/hive-104500/@bravetofu/re-clayboyn-sr38gm