I concur not only that if you don't know how to use Xxxx (such as sutures), then leave it home, but would also point out that ou usually shouldn't suture in the field (this from my wife, an MD). Since you can't properly prepare and clean the wound, it's not ready for suturing and suturing is fine to wait a few days will they're at the hospital. Close it up, physically, to minimize bleeding and further contamination, but there's no need to being going all Rambo on your hiking companions, cool though it may seem.
Back to the OP's Q:
I go pretty darn light. Mostly my first aid kit is in my head – how to diagnose the problem and then find a solution with the materials at hand. You can sterilize a cloth in boiling water although bright sunlight would do a lot (or hot wire your steripen!). You also have to improvise on the big, important, life- and limb-saving stuff anyway. You're not going to have a traction splint for broken femur or even a good splint for broken arm unless you know how to use your hiking poles to crate traction on the leg and your inflatable sleeping pad to make an air splint.
Take a wilderness first aid class that includes AT LEAST two practical sessions – victims with scripts, helpful with make up on as well. You will feel like you've been through the wringer, but you'll also be much more ready when something bad does happen. I'd have students bring their packs packed for a normal trip and THAT was what they had to use to treat the injuries and illnesses they encountered.
a bandaid or two, some adhesive knit (for friction) and moleskin (for pressure points). Benadryl (and knowing when to use it) is probably the single most useful drug (hives, sleep-inducer, reducing nasal congestion,anaphylactic shock, etc. Some NSAIDs Some Imodium if they have the runs and some Ex-Lax if they need to.
We "packed for bear" on a private Colorado River trip. Serious drugs, fast-clotting dressings, sutures, hypos, I think there were two IV set-ups. And two MDs. Partly that was figuring that in addition to our 16 people for 16 days, we might encounter other parties with older, sicker or less well prepared people and we (especially the two MDs) would feel horrible not being able to help out more. The biggest issue was jock-itch-of-the-chest due to wearing wet clothes and life jackets in warm weather for 12 hours a day. To others, I'd recommend a little more topless sunbathing to let the UV in sunlight beat down the fungus.
Edited to add: First aid tape? Just wrap duct tape around your water bottle. It will "manscape" you when you remove it, but you won't do that until you're back in town. A fair number of hunters up here just bring duct tape and super glue to be used as a bandaids and sutures. And other repairs as needed.