It may be an approach to deal with the issue, but I think it may make things to complicated. Not every ritual even needs a "combat application" (attack or utility power doesn't matter really). Some may benefit from it.
What I might do:
1) Everyone can cast rituals. You normally need material components, focuses, a ritual scroll and possibly a skill check, so it's not necessarily easy or effective if just anyone can do it.
2) You can become a "Ritual Caster" (may be a feat, class ability, or some other character build option). This will give you the ability to prepare rituals in advance (possibly at reduced cost) and cast them more quickly. You can never really prepare many rituals. So a spellcaster has to carefully decide which rituals he really needs quickly, and can prepare them in advance. If you think Knock and Arcane Lock can be useful spells to cast on a moment's notice, you can do that.
Following exception-based design - some rituals may have limitations on how good they work as prepared spell. Maybe a spell that you could use to create a wall requires several rounds to cast (since a Wall spell is pretty strong.) While Knock is something you cast in a single round.