When something is restricted in some way, and you enjoy it, you try to value it in any way you can.
When it suddenly becomes free, most of it's value is gone. Also, some people will take it as seriously as ranked, which could be a really, REALLY bad thing. I would prefer everyone goes full damage and the fun times ensue, but some people think to build raid boss tank or kill-you-heal-all-damage builds, which makes it more irritating than fun.(in my opinion)
Basically people play or get something, for the most part, when it's released,and if it's kept many people will try to find the "pro way" to play it. When it's just there, being available, many people forget about it. It loses value, and people think to re-add that value by "finding the pro way" to win. For now, I believe URF should stay something for the April fools.
... unless Rito's improvement made it 2x better, in which case I would replace rift with URF.