I'd say, Lost Lore is pretty inoffensive? It doesn't hurt anyone and gives you some free if mostly useless stuff. I dislike the music game thing a lot more, because it actually requires me to do something for subpar rewards, as opposed to Lost Lore which does everything itself.
But I also agree that HoF is the best event type. The only thing that bothers me about that statement is that the best event is somehow one where you can't use you own units? I think it's a glaring flaw of the game, that after these years, they still didn't find a way to use my own level 40+10 characters in a fun way, that's not getting stomped by them or completely stomps them. Arena exists I guess, but it's not really interesting in any way.
I enjoy the little "Do one battle for flowers for every character you unlock"-Mode (sorry, I play in German, and don't want to look up English names for modes), because it actually gives me interesting challenges to work out sometimes, especially if the character I have to get two kills for is one I don't want to 5*.