I'm with aluminium persuader on this.
The main problem with flying suits, so far as I'm concerned is that they are all so military-looking and all made in one piece. No wonder people laugh at the flying suit wearer when he/she climbs out of a Pa28 in such attire.
A flying suit has three functions; as an overall, a source of extra storage pockets and as fire protection.
First of all, where there are aeroplanes there is oil. You invariably get your trouser legs spashed even when just checking the engine oil level. I'm sick of having to use dry-cleaning fluid to remove oil from my pants.
If you are sufficiently thorough as to get down on your knees to examine the U/C and the underside of the aircraft during pre-flight, you get grass stains.
I always wish I had extra pockets, if only for a torch and the extra spectacles my licence requires that I should carry.
Many aeroplanes have the fuel tank in the nose, right behind the engine. If you do have a crash, the first thing to arrive at the scene of the accident is the propeller, then the red hot engine, then the fuel tank - and then you've guessed it - the pilot! All in a heap together. What a combination.
In the summer, it can be too hot to wear a one piece flying suit. You may only wish to wear the pants with a nomex shirt (that racing drivers can already buy). For a female pilot, a one piece flying suit is a nuisance when she wishes to use the loo.
In the winter, aerodromes are cold windy places. A windproof suit with (pure) woolies worn underneath is a good idea. Most glider pilots are so attired for that reason.
I totally agree with aluminium persuader in regard to synthetics. Those of us who remember the Falklands War will remember that burn injuries to naval personnel were very much worse because of the polycotton uniforms they had been wearing. Those shiny satin like nylon flying jackets are a daft thing to wear, (as also are the equally daft cheap synthetic navy blue uniforms the instructors wear all day every day).
If flying suits were designed with the flair and colour of the suits available to amateur racing and rally drivers, everybody would want one.
Gloves too are a good idea, even if only because handling a yoke with slippery sweaty hands is unpleasant. If you have to escape from a burning aeroplane, you will need your hands to remove your headset and seat belt, open the hatch and climb out.
Finally remember that most of the Piper range only have one hatch. If the occupant of the front passenger seat is injured in a non-fatal crash, he/she may be very slow to vacate the aircraft. If you are in the left hand seat, your egress may take far longer than you think.
Broomstick.