As it always seems with Legends, it all looks pretty great but there is just SO MUCH! I've been very nearly a completist with this line over the years, but it is getting really difficult to keep up and I don't have room to display 2/3 of them anyway. I'll be picking and choosing as well. I usually buy up the Spidey themed waves, and I like to try to keep up with new MCU characters if I can. Otherwise I stick to classic versions, which they have covered a lot of. Like you said, figures like the new Scarlet Witch or Magneto look great, but I already have them too, so we'll see.
Off the top of my head, a few I am excited for are Nightcrawler, Scorpion, Hydro Man, X-Factor Cyclops, Cannonball, Classic Loki, Silver Samurai, and the MCU stuff. Also the Dr Doom shown is a more recent version from the comics where he was more heroic and went by the "Infamous Iron Man" while Tony Stark was down for the count.