Solar is now the best subclass for all classes, but only in highly specific builds. You get super high damage with good enemy control and near-immortality if you play your cards right, but I feel like there's too much mental overhead and every build feels like it's going to fall apart if you're missing one piece of it. Plus, Scorch and Ignite are just way too slow to be practical in general gameplay. Void and Stasis are objectively worse, but they feel better because there's less effort involved in maximising the builds, perks/mods can be mixed-and-matched much more freely and all of the "Core Verbs" e.g. Devour, Weakness, Suppression fit into your gameplay loop so much more easily. I'm still riding on the high of the Warlock Thanos Snap build (Lord knows that Fusion Grenade spam got very old very fast), but the Void and Stasis options I used last season get more tempting by the day.