After seeing and reading what people are trying to come up with for first deer rifles or beginners or children's guns I've come to think that an economical, simple bolt action rifle with a little stock adjustability chambered in 30/30 would have a niche. Birch or synthetic stock, maybe removable spacers for butt length, about a 20 in barrel, sights!, with receiver sight option. Add a scope later once they get the fundamentals of marksmanship. The 30/30 would provide a moderate recoil with the capability to take medium game out to reasonable ranges for new hunters.
If ever really outgrown, it would still make a good truck or cabin gun, or set aside for the next generation.
Savage? Ruger? Anyone interested?
All of that is easily accomplished, with the exception of the iron sights, with one of the many .308s out there using special light factory loads or handloads. When Johnny and Sally grow up, they've already got a grown up rifle that they're familiar with. I've also come to the conclusion that the best sights for beginners are red dots. They have unlimited eye relief and are simple and easy to line up on the target. There's also no chance of them getting whacked in the eye from getting too close to a scope. Red dots are easily mounted on Weaver-type bases with square cuts.
