I really enjoy the versatility of Ana's kit; she has no mobility, but she can deny healing, boost healing, offer limited (though very effective) crowd control, heal an incredible amount of single-target damage from range, deal decent chip damage from range, and deal decent burst damage up close. Those 6 options are actually controlled by only 3 abilities, so she's easy to control. I think some of those options are too strong -- for example, there's hardly a reason to run Mercy if Ana heals just as much (if not more). But fundamentally, I love what she brings to the table, and I feel engaged when I play as her. I just wish her strengths didn't overshadow the rest of the healers -- especially Mercy.
When I play Roadhog, I only have to consider the hook+m1 combo and my spacing for reliable m2s. The question about when to attack and when to peel off to heal has basically the same answer as any other character (I'm hurt / I'm targeted / I'm reloading / I'm on cooldown / My team is gone -- better hide!), so to me, it's not an interesting or unique element of his playstyle. He's very effective and very shallow, and made even more powerful by Ana's strength as a single-target healer.
I don't mean to pick on Hog specifically; there are other heroes that I wish had more utility (such as Widowmaker). I also don't think the game would benefit from bloating every hero a laundry list of niche skills. It's tough to design a hero that feels deep but streamlined, and just as we see with Ana and Hog, it's possible for a hero to feel too strong regardless of how complex they are.