I thought Magneto's attempt to be a dad was pretty funny and even semi-realistic in the second Vision & the Scarlet Witch series, and he was also quite good in "Children's Crusade" trying to reconnect with his semi-grandchildren.
Let's face it, the relationship has been poisoned for both Wanda's fans and non-fans by "Darker Than Scarlet," "Avengers Disassembled," "House of M" and "Axis," which together all make it seem like Wanda is going to be portrayed as insane and vindictive whenever her relationship to Magneto comes up. It didn't have to be that way, but you'll notice in each of those stories Magneto is the reasonable guy trying to calm down his insane daughter. They could revive the relationship in a way that respected both characters, but does anybody really trust any writer or editor at Marvel to do that?
Wanda's fans also have additional resentment because of how the Magneto relationship turned her into a supporting character on "Wolverine & the X-Men" and caused her to be left out of "Avengers: Earth's Mightiest Heroes." That was the low point of the period when it looked like Wanda would just be a minor X-character forever. The MCU may have rescued her to some extent but it still irritates her fans. (Pietro's too, maybe, because he wasn't all that well portrayed on that show.)