If you think it is a problem then maybe you're right. You're better qualified to diagnose a problem than anyone else. If you know there is a problem then you've taken the most important step which is identifying it.
On the rough children front - maybe you need to remind yourself of the benefits that children gain from interacting with children of different ages. As a PP said most older children are careful with younger ones. My boys have an 18 month old cousin and they all have a blast playing together - it's very rare that she gets hurt in fact she hurts them far more often than they hurt her.
On the cuddles with adults - I don't think that it's a big deal but as she matures your daughter will really benefit from relationships with adults outside the family unit. In her teenage years having access to sympathetic 'aunts' might be really useful to you and her. Even though it's hard you need to try and nurture those relationships now for the years to come.