I'd like to point out that the dynasties are much harder than a normal legacy since in a normal legacy all you need to do is reproduce across 10 generations. The only 'handicaps' in a normal legacy are you must randomly roll for traits each time and you need to start with only 1300 Simoleans in cash.
If you're looking for something harder than a dynasty, try the
Apocalypse Challenge. The Apocalypse Challenge requires lots and lots of beforehand planning and is very easy to fail since it contains so much depth.
If you're looking for diversity from your current playstyle, try the
Difference In The Family Tree challenge or one of its spin-offs. Or, make your own! The idea is basically to have each Generation be different from the last and accomplish something new.
Right now I'm playing the
Random Legacy challenge. It's great since it forces me to try things I've never done before. Plus, it doesn't have all of the extra rules that DITFT does and every time you play it, it'll be unique.
If you're doing just a normal legacy, I'd put an extra spin on it like a color code or a family trait. But you can choose anything you want.