I've discussed this before, but it's so pressing for me whenever I run D&D 5E battles, that I think about it often. I dislike Legendary Resistance. A lot. It is probably my least favourite thing about D&D at the moment, and I've never been a massive fan of the system. I like 5E more than most, and am now coming to the end of my 3rd year running it, but Legendary Resistance keeps me mad.
I won't labour the point, but the main reason I dislike Legendary Resistance is that it needlessly takes away a player's shiny thing. They get to use an ability, and the GM just gets to tell them that it doesn't work.
I tried, in my last article on the subject, to fix this with a few different methods. I've now scrapped all of those workarounds, and come up with a new alternative which I prefer a lot more.
Legendary Resistance (3/day). [Creature] gains advantage on a saving throw of their choice. This advantage may be in addition to advantage they already had, allowing them to roll up to three dice, and choose the highest result.
And just in time for Strahd.