There are as many opinions about caliber and bullets as there are calibers and bullet types. Actually, I suspect that if there are N options, there are probably at least N+1 opinions.
Lots of folks hunt hogs with small (<.25 caliber) weapons. Usually they add a statement to the effect that "It's all about shot placement" and that's certainly true. My problem is that I'm not the world's best shot, and the hogs don't seem to make much of an effort to make it easy for me. They keep moving and shuffling around when they're feeding, or they're quartering away, or some other such nonsense that prevents me from making a nice head shot right behind the ear every time.
I hate that, but what can I do? My answer is to carry a .30 caliber rifle. I don't use premium bullets, just regular old soft points, but when I hit them with a large bullet it usually leaves a mark! I bought an AR-15 a few years ago. I liked carrying it. It was lightweight and accurate and I shot a hog with it. It wasn't a large hog, maybe 65 Lbs. It was moving around about 95-100 yards away and I had to just shoot for center mass. I hit center mass, and then the hog took off across a pasture. I shot it again and it went down. When I got to it I had to shoot it again to finally kill it. I sold the AR-15 to my brother and bought an AR-10. It's noticeably heavier to carry, but it throws a heavier (3X) weight bullet. It's my primary hog gun now.