Fitz's D&D5e House Rules

Although in general I'm fairly satisfied with D&D 5th Edition, there are some issues that I think need to be addressed, either because I think the by-the-book solution is too lame for words, or because I feel that a modified solution would suit the desired campaign feel better.



Initiative : minus 1d6 + spell level
So, if you're casting a cantrip, your initiative score is reduced by 1d6. If you want to cast a level three spell, your initiative count would be 1d6+3 less.
Note that if you're casting spells, you get no bonus (or penalty) to your initiative roll for DEX. So whatever you roll on the d20 is it, modified by the spell you're trying to cast.
Spells cast as a Reaction (e.g. Feather Fall) don't have any effect on intiative.
If you take damage, or have to endure some sort of environmental hardship before your initiative comes up, you must make a Concentration save to be able to cast the spell. If you fail, your action is used, and the spell is not cast (though neither the spell slot, nor any material components, are used up). You can still move and take reactions and bonus actions if appropriate.
Rituals : casting time is one hour per total levels plus 1d4 hours.
For example a level 4 ritual would take 1+2+3+4=10+1d4 hours to cast. Note that partaking in a ritual, either as caster or recipient, does NOT count as resting.
Corruption : casting without a patron or other than via ritual may result in corruption.
When you cast any spell, make a DC 5 + spell level save vs. your magic-using characteristic. If you fail, you gain one point of Corruption. I'll let you know what that means as and when it occurs.
Note: Warlocks, Clerics, and Paladins are deemed to get their magic through magical intermediaries. Other spell-casters will have to come to their own arrangements if they want a patron, the most common being a familiar of some kind, which acts as a magical buffer as long as it's within line of sight and thus removes the risk of corrupting one's own self with all this magical jiggery-pokery.
Less savoury wizards can also employ flunkies and minions as "corruption sinks" to avoid the nasty effects on themselves. This sort of behaviour can't be seen as anything less than icky, but it does avoid the problems around the deviousness and trickiness of the sorts of familiars they'd be likely to attract.
There are rituals designed to remove magical corruption, or to transfer it to some other unfortunate.