...They should not just cost gold and and any personal resource should not always come from the caster. Say teleport is a ritual then if you need some kind of personal resource like XP or healing surges it should come from everyone who is going to be teleported...
I like this idea!
• A ritual should cost a specific
something, not a generic portion of gold. The eye of a dragon, the heart of a troll, a relic of the chief saint of a particular deity. Things tied to the campaign world that create a story unto themselves. (They are also things that should innately limit who can perform the ritual).
• A ritual should typically involve more subjects than a single caster (although it does not always have to). You might have a chief performer of the ritual (the one with the lore and arcane/divine/primal power to perform it), but other willing subjects (and with darker rituals not so willing subjects) should be able to contribute to it using a variety of their personal resources.
• A ritual should have a particular flavour, be it arcane, divine or primal. Arcane should be linked to darkness, mystery, places where one should not go. Divine should be celestial/infernal and faith-based, linked to the heavens/hells and gods and be powered by these entities. Primal is of the earth and fey, and of natural influence, guided by the spirits of the First World/Feywild.
• Rituals take a varied amount of time from about a minute to days or perhaps even years in stranger circumstances. The chief thing here is to delineate between magic that can be easily cast in combat and magic that requires greater preparation. This is not to say that the ritual's primary effect cannot be manipulated to induce further secondary effects in a combat situation, but that the genesis of the primary result is typically out of the combat round structure.
The idea that something like knock is a ritual is a no go in my book.
I can see it as a ritual that imbues an enchantment upon a golden key, resulting in an "open locks" check to whoever holds and uses the key. It gives a modifier to the holder (but a modifier less than that of a "rogue") that when used successfully dissipates the enchantment upon the gold key. What should the ritual cost aside from the golden key focus? How should it be limited in terms of duration/time to perform? Should it be a ritual that uses up one (or possibly more) spell slots as part of its performing as a way to limit its repeatability?
One of the ideas I have played around with raise dead is that to bring back the dead requires volunteered life essence so you want a party member back are you all willing to give up a level to fuel it.
Very costly (or not depending) but I think the general concept is excellent in capturing the flavour of rituals, allowing the ritual caster to "shine", but also keeping the party importantly involved and a stakeholder in the situation.
Best Regards
Herremann the Wise