As pointed out by other people rituals seem to have skill requirements and cost requirements and don't seem to be combat orientated (from what we can gather) so it wouldn't be optimising a character, more optimising the party's options.
I think the whole ritual idea gives rise to the idea of the ritualist class, someone who does rituals quicker / cheaper / better or am i approaching that from a 3rd ED perspective.
Although with 4th EDs powers being concentrated on combat perhaps those would be put to the utility powers so once a day they could knock X off the price if they spend upto Y healing surges? and perhaps one to increase the bonuses if other people participate, a class feature to have all skills treated as trained when used in a ritual.
I think the concept is a strong one, in terms of fantasy archtypes, perhaps it would fit better as a paragon path.
For combat, perhaps if rituals are tied to creating magic weapons perhaps they could have combat spells which imbue weapons to increase the + or give it a different ability.