UngeheuerLich
Legend
Oh absolutely, Bless is absolutely broken with bounded accuracy, but it tends to get ignored because of small sample sizes. That's why I chose it, it's easier to look at it's effect over a single day of combats than the value of a +1 to hit. When you get to the point that every combat can have Bless going, bounded accuracy is a joke, but you rarely hear complaints about it, because it's just one more tool in the player's arsenal.
Bless is worth about a +1 modifier to strength so it seems.
Actually bless is not broken at all. At least not on the offensive side. And probably not even on the defensive side.
1. It takes an action to cast.
2. It only improves to hit by 5 to 20%, so it only has a real effect in 1 to 4 in 20 attacks.
3. It takes your concentration slot.
4. Usually you should include yourself because most (or all) classes with access to bless have poor con saves.
So it is only really effective if you can precast it before combat or the combat is drawn out and you can keep concentration. It is also only really effective if your allies can do a lot of and high damage attacks.
Those are many ifs attached to the spell.
Your action could be spend on direct damage spell that could have killed the enemies directly, preventing damage or spells coming at you. Your concentration slot could be something which can be cast as a bonus action.
I don't want to say that bless is a bad spell, it is far from bad. But if it were worse, it would just be a trap option.