Am I expected to stay on glide slope for landing in a light aircraft?
It is more important that your approach is stabilized and safe than you are strictly on slope (i.e. two red/two white). But let's discuss a few things before extending this answer.
ATC is not terribly concerned with where exactly you touch down (especially in a light aircraft) so long as you don't run off the end of the runway. When cleared to land the whole length of the runway is yours to work with:

If receiving “cleared to land” instructions from ATC, you are
authorized to use the entire landing length of the runway and should
disregard any LAHSO holding position markings located on the runway.
If you receive and accept LAHSO instructions, you must stop short of
the intersecting runway prior to the LAHSO signs and markings.

Different runways will call for different touchdown situations which is why it's important in preflight to understand what your landing distance and roll out will be.
In any aircraft you fly you should be proficient (or learning to be proficient) in various landing techniques than includes standard approaches as well as no flap approaches and short field landing maneuvers. If you have all these things in your toolkit you will be fine. If you are proficient in an aircraft you should be able to put it down on the numbers or the 1000 foot markers or any other spot your instructor asks you to demonstrate so long as there is sufficient distance to roll out and stop. You should focus on being able to deliberately put the aircraft down on a spot of your choosing rather than thinking of it in terms of &quot;i always end up touching down on the mid point of the runway&quot; as the latter statement means a very different thing on a 2000 ft runway than it does on a 10,000ft runway. This can generally be controlled with small pitch and power changes on final.
Generally speaking you should fly the glide path if it is available to you as this will guarantee obstacle clearance and keep you safe. While it is never bad to be a bit above glide path (three white, one red) it can be problematic to be very high (all white). The issue with 4 white lights on a PAPI is there is no further indication of how far above glide path you actually are. Making the assumption that you are anywhere near the glide path if you see 4 white lights is dangerous and can lead to a fast, unstable, slam dunk approach. Slope adjustments can be a bit delayed on approach and a power increase will generally bring you back up to slope if you are low while chopping the power will bring you down to slope but remember it will take some time to settle in so you need to think ahead of the airplane.
If you put it all together you will see that staying on slope brings you down to the 1000 'footers, keeps you clear of obstacles, and allows you to make small final adjustments to control your touch down if you want to land a bit short or a bit long.
It is not a question of focusing on one OR the other but focusing on both and realizing how they play together. If you come in on slope you can make small power changes to adjust your aiming point and suit your desired maneuver.
The FAA's Approach And Landing Chapter of the Airplane Flying Handbook has lots of good info on the matter and is worth the read.

Stabilized Approach Concept
A stabilized approach is one in which the pilot establishes and maintains a constant angle glide path
towards a predetermined point on the landing runway. It is based on
the pilot’s judgment of certain visual clues and depends on the
maintenance of a constant final descent airspeed and configuration.
An airplane descending on final approach at a constant rate and
airspeed is traveling in a straight line toward a spot on the ground
ahead. This spot is not the spot on which the airplane touches down
because some float occurs during the round out (flare). [Figure 8-9]
Neither is it the spot toward which the airplane’s nose is pointed
because the airplane is flying at a fairly high AOA, and the component
of lift exerted parallel to the Earth’s surface by the wings tends to
carry the airplane forward horizontally.


To address some points of your directly:

I thought that's what flaps were for - to allow for a steeper approach.

Flaps allow you to fly a steeper decent angle at a given airspeed, this is not a blanket security measure to fly arbitrarily steep approaches at 80Kts in a 172. They also help you to generate more lift at a given airspeed so you can fly a standard approach at a slower than normal speed (think short field landing).

...and approaching exactly on glide
slope usually means I have to add power on short final because I start
getting too low.

If you are on glide slope on short final you are not too low (thats the point of a glide slope). If you are high for most of the approach, cross the slope, then find your self sinking below slope your approach is not stabilized and you are likely coming in hot then cutting power and diving for the runway.

I kinda like being a little higher

While there is no strict regulation on flying above glide slope flying arbitrarily high is typically an indication of an unstable approach that will result in a slam dunk dive final. The glide slope exists for many reasons and should be followed for those reasons.
If you are student pilot (you dont mention here) work on flying stable, on slope approaches. If you already have your ticket I would start some Instrument training and understand what its like to fly the slope in the soup (or foggles) and how being high can be a real issue when you break out, it might help put it all into perspective.