It's valid feedback. Especially in BG3 where ST/conc spells are much weaker than attack roll/auto damage spells.
Most casters in 5e want to take the War Caster Feat, which gives Advantage on Cont STs. This gives you a ~75-85% chance to succeed on Con saves.
However, this doesn't help with only being able to cast 1 concentration spell, this is true. Especially bless vs bane, Bless is ~strictly better because it doesn't have any chance of failing whereas Bane can be resisted by enemies.
