Ronin 4-Heel-25 mm Forefoot-15 mm
Ronin 3-Heel-25 mm Forefoot-15 mm
Musha 4-Heel-22 mm Forefoot-13 mm
Brooks T7-Heel-23 mm Forefoot-12 mm
Nike Lunaracer-Heel-24 mm Forefoot-17 mm
AdiZero Mana 6-Heel-25 mm Forefoot-16 mm
The ones you were considering do not have more cushioning than what you're currently in so I listed some that do. I've never worn the Mana but looking at pictures of it it looks a little stiff, which you're trying to avoid. The LunaRacer is flexible and has a little more in the forefoot but the softness of the cushioning is off putting to a lot of people, including myself. It's tough to find a racer with more in the forefoot than the Ronin because it's basically a cut down trainer for people who don't want to go all the way down to a normal racer.
If though you really want more flexibility and more in the forefoot you could go off the deep end like I did and try the Newton MV2, which is zero drop and has an 18 mm forefoot. I hated all the Newtons I ever tried on until this one but it's now my favorite shoe. Warning though, it's flexible but the cushioning is very firm so if you don't give yourself time to get used to them you'll take a beating. Also the zero drop takes time for your calves to adjust to. And on top of that the lugs in the front take some getting used to but I don't even notice them anymore. I'm not trying to scare you away from them, they're my favorite shoe. But I also don't want to come off as one of the wacko Newton evangelicals you so often see.