My husband hates the smell too. I do mine in a pressure cooker, now more often when he's at work...

The gel, in particular with chicken, seems to vary a lot based on how concentrated it is (how much water to bone) and yes, the addition of chicken feet does help. I re-use the feet twice though. I also add the chicken skin to the broth since no one in my family likes to eat it (and it contains collagen)

For the beef broth I've recently started adding a small oxtail which adds great flavor as well as gel. I've been using the beef broth in some specific recipes that need the beefy flavor so the extra cost is worth it (I use it to make a coconut amino substiute and since coconut aminos are insanely expensive in Europe I figure the small cost of the oxtail is worth it).

For both he beef and chicken you get better flavor if you use a little meat (can be the grisly bits you cut off and leave on your plate - I'm not talking about anything expensive). I don't always do that but I do try to grab a few little bits.