Necessity of Sleeping Pads?

That might be doable in milder conditions, especially with a good layer of duff, moss, or even pine needles, but you'd likely freeze in Winter.

How cold might some of your nights be? One of the critical uses of a sleeping pad (apart from comfort and quality of sleep) is keeping your body from losing heat from beneath you. I would argue this is a factor even when the night time low is in the 50s Fahrenheit but it only gets more important the lower then temperature is.

I did no pad many times when younger, sometimes in winter. I froze.

You might be able to fit the pad inside if it's the first thing which goes in. Let it unroll, then fill the "burrito" with your gear. Or, fold it up against your back panel and stuff your gear in.

Consider a new piece of gear. :) I just use an inflatable air mattress which is the size of a 1 liter Nalgene bottle when rolled. I never have problems packing it.

Never.
Used to use an older model z-rest which folded up into a rectangle but got tired of trying to find a spot for it on the outside of my ULA CDT pack. Went with a Neo Air which rolls up about the size of a 32 oz nalgene and will easily fit anywhere in or on my pack. Nice and warm and soft, too!

In the far past I used a .5 inch heavy foam pad. Now I use a Neoair or Kookabay plus a thin GG pad. Comfort and insulation, small and light. Or make a natural bed with materials at hand but leaving a trace.

If you hammock, you can leave the pad at home and use an underquilt instead. ;)

If you really hate carrying a sleeping mat, just empty out your backpack and use the Pinnacle 50's frame to keep your torso off the ground. Problem solved.

too warm?

I always have pad.

I use a small Prolite in conjunction with a Z-seat sit pad for my feet. The Prolite takes up very little space and is just enough padding and warmth. I typically load it completely uninflated and folded and placed against my back. My pack liner goes in next, so the pad is nicely tucked in for the trip. It can be rolled to near Nalgene size and tucked into a cranny. Folded in quarters it is 12"x20"x5/8" and that can be varied to your pack size. If your pack is loose, you can load it with the valve up and add a little air stiffen it all up a bit. You can do the "round column" loading trick too and inflate to suit. 11oz on my scale.

The Z-seat has been so handy for sitting, a clean foot pad to change socks and clothing, a cozy for bagged dinners, kitchen table, and extending my sleeping pad. It rides in the outer pocket of my pack, folded in half and ready to deploy at a rest stop. It is 1.9oz that I can afford.

Spelt quipped, "If you hammock, you can leave the pad at home and use an underquilt instead…."

He's already space challenged so the hammock and accessories would send him over the edge. A comfortable edge, but still :)

I'd probably sleep better on a pad with just a light jacket than I would without a pad and in an appropriately rated sleeping bag. Makes a large difference.

I often forgot my pad in Scouts; I was often uncomfortable and cold on Scout trips.