Most of the time you're just better off dipping your weapon in fire, or using the copious amounts of basic poison laying around. I don't imagine I'd waste my concentration and a spell slot for three rounds of 1d4 radiant damage, but I guess sometimes radiant is better. I believe the duration of Divine Favor is supposed to be one minute, no less.
Overall, all the spell nerfs don't make a great deal of sense given all the indirect nerfs to spells Larian has inflicted on us. Movement is so cheap in BG3, given ridiculous jumping distances and all the movement boosting items, nullifying battlefield control. Durations and effects have been slashed and degraded almost across the board. And the means of removing such effects have also been trivialized, by and large. Concentration can be an absolute pain in this game. It's all rather annoying, really. Yes, mods will fix most of it, but mods have to be updated post-patch and can lead to other annoyances.