1. champ refund would be great, but let it be 100% refund!
I mean, everyone of us had that WTF moment when they bought a champion that looks great, only to see he won't fit their playstyle and they can't learn to play him good enough. or he just suxx.
however, this would mean you can try out every champ in a single day... so I'd say this "refund" should be limited to once a month.
2. gift system would just not work. I mean is there even a champ NOONE ever bought? No. Ofc not. So it would be a gift for those who did not buy him, and big disappointment for those who have him.
The only "gift" I could think of, is that on Christmas, everyone would get a champ of their choice. I mean, ONCE a year, the first champ you buy after 24. December would be free. Just the first one. It wouldn't be a big deal RIOT, huh?
(10 weeks till Christmas, you have plenty of time to think about it )