Spark plugs don't get dirty with modern fuels and engines, and the gaps don't open up appreciably during their service life. In any case, modern ignition systems can generate enough voltage to cope.
For these reasons, spark plugs have become "fit and forget". Check the gap when new (normally they don't need adjustment and multi-electrode types shouldn't be adjusted) and fit them. Drive 20-40,000 miles then bin them and replace. No need to clean or reset the gaps IME.
As far as engine jobs go, cleaning breathers, changing oil, filters and coolant, plugs, cam belt is all that's required for routine maintenance.
Brake servicing has changed little, as mentioned, except to say that it's very worthwhile taking steps to ensure air doesn't enter the ABS valve body if you're doing work involving disconnecting fluid lines.
Modern cars may look daunting, and have more clutter under the bonnet so access can be awkward, but the myth that you can't do your own maintenance any more is just that. In fact, given the quality of service and cost of taking a car to some main dealers, it's never been more advantageous to do so.
Kevin