Li Shenron
Legend
Underpowered spells.
Really, the true benefit of casting a spell as a ritual is that it doesn't cost a slot. So this should be the case for spells that make you feel expending a slot is a bit too high a price.
Spells that are rarely useful would rather need something different, for example not require to be prepared (which is actually the case for wizards' rituals, but not for others). But if they are very useful on that rare occasion when you need them, why should they not cost a slot?
Really, the true benefit of casting a spell as a ritual is that it doesn't cost a slot. So this should be the case for spells that make you feel expending a slot is a bit too high a price.
Spells that are rarely useful would rather need something different, for example not require to be prepared (which is actually the case for wizards' rituals, but not for others). But if they are very useful on that rare occasion when you need them, why should they not cost a slot?