The 3* tier is in pretty good shape. It’s well balanced, and there are only a few stinkers left. (Sentry being #1 for me. Ragnarok is not great, but he has some decent synergy with the 4* Thor and IM40 team, so there’s at least some utility he brings to the table. Still, I’d much rather bring a stronger green user like KK, Chulk, or Thing.)
Spidey needs work. The issue with him is that he’s set up as a passive support character, but his abilities do not give the same bang for your AP buck that other 3* passive support characters bring you. Spidey is not useless… but then, no character is truly useless. But 12 AP for a 2800 point health bump to the team is costly in a tier where Kamala gives close to 1000 points any time a teammate fires a power for zero AP, Beast gives you 3 protect tiles (if you trigger the power right) and 25% less team health for 11 AP, or Cage can give you close to 7500 damage for one more AP. (Or for 7 yellow AP, Cyclops can spam away red tiles and feed his own 4k eyeblast over and over.) Spidey’s cheap blue stun is worthwhile, and the purple shields are a nice bonus if you’re running a strong purple user like SW or Blade. But the blue stun, in the end, isn’t worth effectively taking two offensive players with you instead of three. And now, with Dr. 3-Star Strange and his 9 AP blue stun that also drains enemy AP and does damage… I don’t see why you’d bring Spidey along anymore unless you had to.
But… the 4* tier – which is the most numerous tier now – needs a LOT of work. There are characters that I’ve never seen in the wild (other than their PvP events) because their utility is marginal or zero. There are characters who are so close to being something cool (Drax, Mr. Fantastic) but pull up short in the end. There was Cho. (Thankfully, Cho has come around 1000% with his revamp.) There are characters who are fun, to an extent, but that slow down match play with excessive animation (Ant-Man, Carnage – who also eats your roster alive unless you plan well), and characters that would be fun if they weren’t so limp or costly or slow-developing or all of the above (Spider-Gwen, Winter Soldier, Miles, original Star-Lord, Kingpin). And characters that are okay, but just don’t stand out from the crowd for some reason or seem to have been passed by (Moon Knight, Spider-Woman, X-23), or which don’t really become effective and useful until you’re in the 10-13 cover range, making them fairly useless for transition players (Red Hulk is a good example of the latter. A few covers – eh, not bad. Lots of covers – defensive giant). And Medusa, and Strange in the 3*, show that Demi can still design great, fun, worthwhile characters, so all of this is not due to lack of ability. There’s a lot more work to be done in 4* land, and I’m hopeful that some of the characters, if not all, will be brought up to a standard where any of them are reasonable characters to bring into PvE or PvP.