Not saying you aren’t wrong about O2’s sun phase needing a nerf, but the classes IMO that suffer the most in there are trickster and rogue; their lower HP than the sworders give them as tough a time, so that’s not only a melee thing. And chase phase in a small/weak group: best tactic is drag O2 to the (cleared) central corridor and you can damage him and heal up at your leisure.
On the Tunnel Rat Marks: for what it’s worth I saw more people saying they needed a Geb mark, due to fame farmers not wishing to go into tombs after they’d maxed. On the last day it was far harder to get a tomb done than an O2 mark. And tomb a tougher dungeon/as reliant on a big/good group to complete as WC.
It’s a leap to assume the 30% Tunnel Rat stat means fewer people achieved Last Call; many may have opted for only LC, due to it offering something guaranteed & unique (the skin) versus only a promise dangled of scalable reward for TR, and O2 being straightforward to farm 5x of. That was my strategy, doing LC first, to get that in the bag, before I knew whether I was going to commit to playing further.
Being 0/8 was a far bigger factor than being melee or not in WC, for the rushing which is perilous on most classes until you have some pots drunk. I found it charming/delusional that people thought players would go back to the full clear WC strat. HP scale means it’s better/more efficient to let the 0/8 passengers die & nexus to remove their HP scale contribution; a sad state for a theoretical co-op game to have got itself into.
Knowing now what I know about the season, a melee was the best choice to make, since the meta was so much being in a large mob of players, there was little point being on yet-another-ranged class in the mix.
Warrior was the most useful due to getting between event spawns the fastest, & Paladin desirable for the group buff. Had I known then what I know now I’d have made one of those two, or a samurai to contribute exposed, though I’d have disliked the low spd he has. But I was given false info that it was ‘old’ O2, so chose sorcerer due to thinking I’d end up having to solo things after everyone died off, and also I guess hacked client players cheating extra lives meant the attrition rate wasn’t very noticeable.