I've always been on the fence between crying it out (which both of my children have at some point) and letting the kids just get in bed with us when they need to. It's one thing if they aren't getting the sleep they need while co-sleeping. But it's also not good for them to be scared and for parents to refuse the basic hug and cuddle that a kid might need after a bad dream.
For the most part, our kids don't sleep in the bed with us, but they have both gone through stages where they did (usually about 3-9 months old and occasionally since then). A few nights ago we kept having thunderstorms at bedtime and the kids were getting scared. So one night, we had our oldest on the floor of our room in a sleeping bag and our youngest in bed with us.
Early this morning, my husband woke me shortly after 1am, when he brought our youngest in bed with us. He had been wandering downstairs and was scared (either from a dream or not being able to find us. So, he ended up in bed with us. After no sleep issues the first few weeks in our new house, he has gotten in some really bad habits of getting up. Really, all he wants is someone to sleep next to him in his room.
Honestly, most families not that long ago slept in groups in mattresses on the floor. Maybe there were 5-8 kids and at least 2 adults and at the most 3 bedrooms. We've conditioned ourselves to expect privacy and individual rooms, but that's not always the best solution for a good night's sleep. Of course, neither is having them in bed with you, as my husband who got kicked in the eye this morning could tell you.
We were made to be close to each other. Privacy is great when you're a teenager, but I have a hard time sleeping if my husband isn't in bed yet. Even as an adult, there are times I just want to snuggle with my mom. So, when one of my children are really truly scared or hurt or worried, I let them snuggle and sleep. Even if it's only for a few minutes. They'll only be little for a short time, so snuggle while you can.